#include <iostream>
#include <cstring>

using namespace std;
const int mod = 1000000007;

long long p, a, b, ans;

int main(){
    string str;
    cin >> str;

    for(int i = 0; i < str.size(); i++)
      if(str[i] == 'P') p ++;
      else if(str[i] == 'A') a += p;
      else ans = (ans + a) % mod;

      cout<<ans<<endl;
      return 0;
}