#include <bits/stdc++.h>
using namespace std;
const long long MOD = 1000000007;
int main(){
  int N;
  cin >> N;
  string S;
  cin >> S;
  string T = "yukicoder";
  vector<string> T2;
  T2.push_back(T);
  for (int i = 0; i < 9; i++){
    string TT = T;
    TT[i] = '?';
    T2.push_back(TT);
  }
  long long ans = 0;
  for (int i = 0; i < 10; i++){
    vector<vector<long long>> dp(N + 1, vector<long long>(10, 0));
    dp[0][0] = 1;
    for (int j = 0; j < N; j++){
      for (int k = 0; k <= 9; k++){
        dp[j + 1][k] += dp[j][k];
        dp[j + 1][k] %= MOD;
        if (k < 9){
          if (S[j] == T2[i][k]){
            dp[j + 1][k + 1] += dp[j][k];
            dp[j + 1][k + 1] %= MOD;
          }
        }
      }
    }
    ans += dp[N][9];
  }
  ans %= MOD;
  cout << ans << endl;
}