#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include<iostream>
#include<string>
#include<cstdio>
#include<vector>
#include<cmath>
#include<algorithm>
#include<functional>
#include<iomanip>
#include<queue>
#include<ciso646>
#include<random>
#include<map>
#include<set>
#include<bitset>
#include<stack>
#include<unordered_map>
#include<unordered_set>
#include<utility>
#include<cassert>
#include<complex>
#include<numeric>
#include<array>
#include<chrono>
using namespace std;

//#define int long long
typedef long long ll;

typedef unsigned long long ul;
typedef unsigned int ui;
//ll mod = 1;
//constexpr ll mod = 998244353;
constexpr ll mod = 1000000007;
const int mod17 = 1000000007;
const ll INF = (ll)mod17 * mod17;
typedef pair<int, int>P;

#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define Rep(i,sta,n) for(int i=sta;i<n;i++)
#define rep1(i,n) for(int i=1;i<=n;i++)
#define per1(i,n) for(int i=n;i>=1;i--)
#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)
#define all(v) (v).begin(),(v).end()
typedef pair<ll, ll> LP;

using ld = double;
typedef pair<ld, ld> LDP;
const ld eps = 1e-10;
const ld pi = acosl(-1.0);

template<typename T>
void chmin(T& a, T b) {
	a = min(a, b);
}
template<typename T>
void chmax(T& a, T b) {
	a = max(a, b);
}
template<typename T>
vector<T> vmerge(vector<T>& a, vector<T>& b) {
	vector<T> res;
	int ida = 0, idb = 0;
	while (ida < a.size() || idb < b.size()) {
		if (idb == b.size()) {
			res.push_back(a[ida]); ida++;
		}
		else if (ida == a.size()) {
			res.push_back(b[idb]); idb++;
		}
		else {
			if (a[ida] < b[idb]) {
				res.push_back(a[ida]); ida++;
			}
			else {
				res.push_back(b[idb]); idb++;
			}
		}
	}
	return res;
}
template<typename T>
void cinarray(vector<T>& v) {
	rep(i, v.size())cin >> v[i];
}
template<typename T>
void coutarray(vector<T>& v) {
	rep(i, v.size()) {
		if (i > 0)cout << " "; cout << v[i];
	}
	cout << "\n";
}
ll mod_pow(ll x, ll n, ll m = mod) {
	if (n < 0) {
		ll res = mod_pow(x, -n, m);
		return mod_pow(res, m - 2, m);
	}
	if (abs(x) >= m)x %= m;
	if (x < 0)x += m;
	//if (x == 0)return 0;
	ll res = 1;
	while (n) {
		if (n & 1)res = res * x % m;
		x = x * x % m; n >>= 1;
	}
	return res;
}
//mod should be <2^31
struct modint {
	int n;
	modint() :n(0) { ; }
	modint(ll m) {
		if (m < 0 || mod <= m) {
			m %= mod; if (m < 0)m += mod;
		}
		n = m;
	}
	operator int() { return n; }
};
bool operator==(modint a, modint b) { return a.n == b.n; }
bool operator<(modint a, modint b) { return a.n < b.n; }
modint operator+=(modint& a, modint b) { a.n += b.n; if (a.n >= mod)a.n -= (int)mod; return a; }
modint operator-=(modint& a, modint b) { a.n -= b.n; if (a.n < 0)a.n += (int)mod; return a; }
modint operator*=(modint& a, modint b) { a.n = ((ll)a.n * b.n) % mod; return a; }
modint operator+(modint a, modint b) { return a += b; }
modint operator-(modint a, modint b) { return a -= b; }
modint operator*(modint a, modint b) { return a *= b; }
modint operator^(modint a, ll n) {
	if (n == 0)return modint(1);
	modint res = (a * a) ^ (n / 2);
	if (n % 2)res = res * a;
	return res;
}

ll inv(ll a, ll p) {
	return (a == 1 ? 1 : (1 - p * inv(p % a, a)) / a + p);
}
modint operator/(modint a, modint b) { return a * modint(inv(b, mod)); }
modint operator/=(modint& a, modint b) { a = a / b; return a; }
const int max_n = 1 << 20;
modint fact[max_n], factinv[max_n];
void init_f() {
	fact[0] = modint(1);
	for (int i = 0; i < max_n - 1; i++) {
		fact[i + 1] = fact[i] * modint(i + 1);
	}
	factinv[max_n - 1] = modint(1) / fact[max_n - 1];
	for (int i = max_n - 2; i >= 0; i--) {
		factinv[i] = factinv[i + 1] * modint(i + 1);
	}
}
modint comb(int a, int b) {
	if (a < 0 || b < 0 || a < b)return 0;
	return fact[a] * factinv[b] * factinv[a - b];
}
modint combP(int a, int b) {
	if (a < 0 || b < 0 || a < b)return 0;
	return fact[a] * factinv[a - b];
}

ll gcd(ll a, ll b) {
	a = abs(a); b = abs(b);
	if (a < b)swap(a, b);
	while (b) {
		ll r = a % b; a = b; b = r;
	}
	return a;
}
template<typename T>
void addv(vector<T>& v, int loc, T val) {
	if (loc >= v.size())v.resize(loc + 1, 0);
	v[loc] += val;
}
/*const int mn = 2000005;
bool isp[mn];
vector<int> ps;
void init() {
	fill(isp + 2, isp + mn, true);
	for (int i = 2; i < mn; i++) {
		if (!isp[i])continue;
		ps.push_back(i);
		for (int j = 2 * i; j < mn; j += i) {
			isp[j] = false;
		}
	}
}*/

//[,val)
template<typename T>
auto prev_itr(set<T>& st, T val) {
	auto res = st.lower_bound(val);
	if (res == st.begin())return st.end();
	res--; return res;
}

//[val,)
template<typename T>
auto next_itr(set<T>& st, T val) {
	auto res = st.lower_bound(val);
	return res;
}
using mP = pair<modint, modint>;
mP operator+(mP a, mP b) {
	return { a.first + b.first,a.second + b.second };
}
mP operator+=(mP& a, mP b) {
	a = a + b; return a;
}
mP operator-(mP a, mP b) {
	return { a.first - b.first,a.second - b.second };
}
mP operator-=(mP& a, mP b) {
	a = a - b; return a;
}
LP operator+(LP a, LP b) {
	return { a.first + b.first,a.second + b.second };
}
LP operator+=(LP& a, LP b) {
	a = a + b; return a;
}
LP operator-(LP a, LP b) {
	return { a.first - b.first,a.second - b.second };
}
LP operator-=(LP& a, LP b) {
	a = a - b; return a;
}

mt19937 mt(time(0));

const string drul = "DRUL";
string senw = "SENW";
//DRUL,or SENW
//int dx[4] = { 1,0,-1,0 };
//int dy[4] = { 0,1,0,-1 };

//------------------------------------

vector<int> trans(vector<int> v) {
	rep(_, v.size()) {
		rep(i, v.size())if (i + 3 < v.size())if(i>0) {
			if (v[i] == v[i + 1] && v[i+1]==v[i + 2] && v[i + 2] == v[i + 3]) {
				if (v[i] != v[i - 1]) {
					for (int j = i; j <= i + 3; j++)v[j] = v[i - 1];
				}
			}
		}
	}
	return v;
}

modint sol_naive(string s) {
	int n = s.size();
	rep(i, n) {
		int t = s[i] - 'A';
		t -= i; t %= 4; if (t < 0)t += 4;
		s[i] = 'A' + t;
	}
	queue<string> qs;
	set<string> st;
	qs.push(s);
	st.insert(s);
	while (!qs.empty()) {
		auto s = qs.front(); qs.pop();
		rep(i, n - 3) {
			if (s[i] == s[i + 1] && s[i + 1] == s[i + 2] && s[i + 2] == s[i + 3]) {

				rep(c, 4) {
					string ns = s;
					rep(j, 4) {
						ns[i + j] = 'A' + c;
					}
					if (!st.count(ns)) {
						st.insert(ns);
						qs.push(ns);
					}
				}
			}
		}
	}
	return st.size();
}
//map<int, modint> mp;

modint sdp[2005][2005];
modint sol(string s) {
	int n = s.size();
	vector<int> v(n);
	rep(i, n) {
		v[i] = s[i] - 'A';
		v[i] -= i;
		v[i] %= 4; if (v[i] < 0)v[i] += 4;
	}
	v = trans(v);
	int c = 0;
	rep(i, v.size()) {
		if (v[i] == v[0])c++;
		else break;
	}
	//coutarray(v);
	c /= 4;
	/*if (mp.find(c) != mp.end()) {
		return mp[c];
	}*/
	rep(i, n + 1)rep(j, i + 1)sdp[i][j] = 0;
	sdp[0][0] = 1;
	rep(i, n) {
		int sup = (i + 1) / 4;
		rep(j, i + 1) {
			sdp[i + 1][j] += sdp[i][j];
			if (j + 1 <= sup) {
				sdp[i + 1][j + 1] += (modint)3 * sdp[i][j];
			}

			//if (i + 4 <= n)sdp[i + 1][j + 1] += (modint)3*sdp[i][j];
		}
	}
	modint ans = 0;
	rep(i, c + 1)ans += sdp[n][i];
	return ans;
}
modint dp[2005][4][4][4];

modint sol2(string s) {
	int n = s.size();
	rep(i, n)rep(x, 4)rep(y, 4)rep(z, 4) {
		dp[i][x][y][z] = 0;
	}
	if (n <= 3) {
		return 1;
	}
	vector<int> v(n);
	rep(i, n) {
		v[i] = s[i] - 'A';
		v[i] -= i;
		v[i] %= 4; if (v[i] < 0)v[i] += 4;
	}
	coutarray(v);
	v = trans(v);
	coutarray(v);
	dp[0][v[0]][v[1]][v[2]] = 1;
	vector<int> oks;
	for (int i = 0; i + 3 < n; i++) {
		if (v[i] == v[i + 1] && v[i + 1] == v[i + 2] && v[i + 2] == v[i + 3]) {
			oks.push_back(i);
		}
	}
	dp[0][v[0]][v[1]][v[2]] = 1;
	rep(i, n - 3) {
		rep(x, 4)rep(y, 4)rep(z, 4) {
			modint val = dp[i][x][y][z];
			rep(t, 4) {
				if (x == t) {
					dp[i + 1][y][z][v[i + 3]] += val;
				}
				else {
					int chk = -1;
					if (x == y && y == z && z == v[i + 3])chk = i;
					else if (i + 4 < n && y == z && z == v[i + 3] && v[i + 3] == v[i + 4])chk = i + 1;
					else if (i + 5 < n && z == v[i + 3] && v[i + 3] == v[i + 4] && v[i + 4] == v[i + 5])chk = i + 2;
					if (chk < 0) {
						int to = lower_bound(all(oks), i + 3) - oks.begin();
						if (to < oks.size())chk = oks[to];
					}
					if (chk >= 0) {
						auto getcol = [&](int loc) {
							int res;
							if (loc < i)res = t;
							else if (loc > i + 2) {
								res = v[loc];
							}
							else {
								if (loc == i)res = x;
								else if (loc == i + 1)res = y;
								else if (loc == i + 2)res = z;
							}
							return res;
						};
						int nx, ny, nz;
						nx = getcol(chk - 3);
						ny = getcol(chk - 2);
						nz = getcol(chk - 1);
						dp[chk + 1][nx][ny][nz] += val;
					}
				}
			}
		}
	}

	modint ans = 0;
	rep(x, 4)rep(y, 4)rep(z, 4)ans += dp[n - 3][x][y][z];
	return ans;
	//cout << ans << "\n";
	/*rep(i, s.size()) {
		int c = v[i];
		rep(j, 4) {
			if (c == j) {
				dp[i + 1] += dp[i];
			}
			else {
				int chk = -1;
				for (int ni = i; ni+3 < s.size(); ni++) {
					if (v[ni] = v[ni + 1] && v[ni + 1] == v[ni + 2] && v[ni + 2] == v[ni + 3]) {
						chk = ni; break;
					}
				}

			}
		}
	}*/
}

void expr() {
	uniform_int_distribution<> udc(0, 3);
	rep(t, 100000) {
		int n = 15;
		string s;
		rep(i, n) {
			s.push_back('A' + udc(mt));
		}
		auto v1 = sol_naive(s);
		auto v2 = sol(s);
		if (v1 != v2) {
			cout << s << "\n";
			cout << v1 << " " << v2 << "\n";
			exit(0);
		}
		if (t % 10000 == 0) {
			cout << "fin " << t << "\n";
		}
	}
}
void solve() {
	string s; cin >> s;
	//cout << sol_naive(s) << "\n";
	cout << sol(s) << "\n";
	//sol(s);
}




signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	//cout << fixed<<setprecision(10);
	//init_f();
	//init();
	//while(true)
	//expr();
	//int t; cin >> t; rep(i, t)
	solve();
	return 0;
}