#include <bits/stdc++.h>

using namespace std;

typedef long long LL;

const int N = 2005, P = 1e9 + 7;

int n, k;
string s;
int f[N];

inline bool Check(char a, char b, char c, char d)
{
    if(a == 'A' && b == 'B' && c == 'C' && d == 'D') return 1;
    if(a == 'B' && b == 'C' && c == 'D' && d == 'A') return 1;
    if(a == 'C' && b == 'D' && c == 'A' && d == 'B') return 1;
    if(a == 'D' && b == 'A' && c == 'B' && d == 'C') return 1;
    return 0;
}
inline bool Delete()
{
    for(int i = 0; i <= n - 4; i ++ )
        if(Check(s[i], s[i + 1], s[i + 2], s[i + 3]))
            return s.erase(i, 4), 1;
    return 0;
}

int main()
{
    cin >> s;
    n = s.size();
    while(Delete()) n -= 4, k ++ ;
    f[n] = 1;
    for(int i = 1; i <= k; i ++ )
    {
        int s = 0;
        for(int j = 0; j <= n; j ++ ) (s += f[j]) >= P && (s -= P);
        (s += s) >= P && (s -= P);
        (s += s) >= P && (s -= P);
        for(int j = n - 1; j >= 0; j -- ) (f[j] += f[j + 1]) >= P && (f[j] -= P);
        n += 3;
        for(int j = n; j >= 4; j -- ) (f[j] = f[j - 3] + f[j - 3]) >= P && (f[j] -= P), (f[j] += f[j - 3]) >= P && (f[j] -= P);
        f[0] = f[1] = f[2] = 0;
        f[3] = s;
    }
    int ans = 0;
    for(int i = 0; i <= n; i ++ ) (ans += f[i]) >= P && (ans -= P);
    printf("%d\n", ans);
    return 0;
}