#include <bits/stdc++.h>
#define rep(i, l, r) for (int i = (l); i < (r); i++)
using namespace std;

typedef long long ll;

int main() {
    int N;
    string S;
    cin >> N >> S;
    ll ans = 0, MOD = 1000000007;
    rep(i, 0, 10) {
        string T = "yukicoder";
        if (i < 9) T[i] = '?';
        //cout << T << endl;
        vector<vector<ll>> dp(N + 1, vector<ll>(10, 0));
        dp[0][0] = 1;
        rep(j, 0, N) {
            rep(k, 0, 10) dp[j + 1][k] = dp[j][k];
            rep(k, 0, 10) {
                if (S[j] == T[k]) {
                    dp[j + 1][k + 1] += dp[j][k];
                    dp[j + 1][k + 1] %= MOD;
                }
            }
        }
        /*
        rep(j, 0, N + 1) {
            rep(k, 0, 10) {
                cout << dp[j][k] << " ";
            }
            cout << endl;
        }
        */
        ans = (ans + dp[N][9]) % MOD;
    }
    cout << ans << endl;
}