#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include <map>
#include <vector>
#include <queue>
#include <deque>
#include <set>
#include <stack>
#include <algorithm>
#include <array>
#include <unordered_set>
#include <unordered_map>
#include <string>
using namespace std;

bool rcmp(int a, int b) { return a>b; }
typedef long long LL;
class mypcmp {
public:
    bool operator()(const int& a, const int& b) {
        return a<b;
    }
};


#define MOD 1000000007
char ib[1024];
int bb[1024];
int main() {
    int n, i, a, b, c, r, k;
    scanf("%d", &n);
    bb[0]=1; for (i=1; i<=n; i++) bb[i]=(bb[i-1]*2)%MOD;
    scanf("%s", ib);
    a=0; r=0;
    for (i=n-1; i>=0; i--) {
        b=ib[i]-'A';
        if (a==b) continue;
        for (k=0; k<3; k++) if (a!=k&&b!=k) break;
        r+=bb[i]; r%=MOD;
        a=k;
    }
    printf("%d\n", r);
    return 0;
}