#include<bits/stdc++.h>
using namespace std;


int main() {
    int n; cin >> n;
    int mod = 1000000007;
    string s; cin >> s;
    string y = "yukicoder";
    string t = "yukicoder";
    int m = y.size();
    long long ans = 0;
    for (int k=0; k<10; k++) {
        vector<vector<int>> dp(n+1, vector<int>(m+1, 0));
        for (int i=0; i<=n; i++) {
            for (int j=0; j<=m; j++) {
                if (j == 0) {
                    dp[i][j] = 1;
                    continue;
                }
                if (i == 0) {
                    dp[i][j] = 0;
                    continue;
                }
                dp[i][j] += dp[i-1][j];
                if (s[i-1] == y[j-1]) {
                    dp[i][j] += dp[i-1][j-1];
                }
                dp[i][j] %= mod;
            }
        }
    
        ans += dp[n][m];
        ans %= mod;

        y[k] = '?';
        if (k) y[k-1] = t[k-1];
       
    }
    cout << ans << endl;
}