#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define X first
#define Y second
#define pb push_back
#define ALL(v) v.begin(), v.end()
#define SZ(a) ((int)a.size())


const int N = 2005, QN = N / 4 + 2;
const ll M = 1'000'000'007;

ll sing[4][N];
ll dp[N][QN];

int main() {
    ios::sync_with_stdio(0), cin.tie(0);

    for (int i = 1; i < QN; i++)
        sing[0][i] = 0;
    for (int i = 0; i < 4; i++)
        sing[i][0] = 1;
    for (int j = 1; j < QN; j++)
        for (int i = 1; i < 4; i++) {
            ll s = 0;
            for (int k = 1; k <= j; k++)
                s = s + (sing[3][k - 1] * sing[i][j - k]) % M;
            sing[i][j] = (sing[i - 1][j] + s * 3) % M;
        }

    string s;
    cin >> s;
    int n;
    n = SZ(s);
    for (int i = 0; i < n; i++) {
        int t = s[i] - 'A';
        t = (i - t + 4) % 4;
        s[i] = 'A' + t;
    }
    int n1 = 0, n4 = 0;
    vector<pair<char, int>> stk;
    for (char c : s) {
        if (SZ(stk) && c == stk.back().X) {
            stk.back().Y++;
            if (stk.back().Y == 4)
                n4++, stk.pop_back();
        }
        else
            stk.pb({c, 1});
    }
    for (auto [x, y] : stk)
        n1 += y;

    // cerr << "n1 = " << n1 << ", n4 = " << n4 << endl;
    
    dp[0][0] = 1;
    for (int i = 0; i <= n1; i++)
        for (int j = 0; j <= n4; j++) {
            dp[i][j] %= M; 
            if (i < n1)
                dp[i + 1][j] += dp[i][j];
            int mul = (i == n1 ? 4 : 3);
            for (int k = 1; k + j <= n4; k++)
                dp[i][j + k] += dp[i][j] * mul * sing[3][k - 1] % M;
        }

    cout << dp[n1][n4] << endl;
}