//

1 #include "iostream" 2 #include "cstdio" 3 using namespace std; 4 const __int64 mod = 1e9 + 7; 5 int n; 6 char str[100010]; 7 int Count[5]; 8  9 __int64 bin(__int64 n, __int64 k)10 {11     __int64 res = 1;12     while(k) {13         if(k & 1)14             res *= n, res %= mod;15         n *= n;16         n %= mod;17         k >>= 1;18     }19     return res;20 }21 22 int main()23 {24     int i;25     scanf("%d%s", &n, str + 1);26     for(i = 1; i <= n; ++i) {27         switch(str[i]) {28         case 'A':29             ++Count[1];30             break;31         case 'C':32             ++Count[2];33             break;34         case 'G':35             ++Count[3];36             break;37         case 'T':38             ++Count[4];39         }40     }41     int Max = max(max(Count[1], Count[2]), max(Count[3], Count[4]));42     int Choice = 0;43     for(i = 1; i <= 4; ++i)44         if(Max == Count[i])45             ++Choice;46     printf("%I64d\n", bin(Choice, n));47 }