#include <iostream>
#include <vector>
#include <string>
using namespace std;
using ll = long long;
constexpr ll MOD = 1'000'000'007;

int main(){
    int n; cin >> n;
    string s; cin >> s;
    const string y = "yukicoder";
    vector<vector<vector<ll>>> dp(2, vector<vector<ll>>(y.size()+10, vector<ll>(n+10, 0)));
    dp[0][0][0] = 1;
    for(int i = 0; i < n; i++){
        for(int j = 0; j <= y.size(); j++){
            for(int k = 0; k < 2; k++){
                dp[k][j][i+1] += dp[k][j][i];
                dp[k][j][i+1] %= MOD;
                if(k == 0 && s[i] == '?'){
                    dp[1][j+1][i+1] += dp[k][j][i];
                    dp[1][j+1][i+1] %= MOD;
                }
                if(j < y.size() && s[i] == y[j]){
                    dp[k][j+1][i+1] += dp[k][j][i];
                    dp[k][j+1][i+1] %= MOD;
                }
            }
        }
    }

    cout << (dp[0][y.size()][n]+dp[1][y.size()][n])%MOD << endl;
    return 0;
}