#include <bits/stdc++.h>
#include <atcoder/modint>
using namespace std;
using mint = atcoder::static_modint<(int)1e9 + 7>;
int n;
string s;
mint solve(const string& tar) {
    int m = tar.size();
    vector<vector<mint>> dp(n + 1, vector<mint>(m + 1));
    for (int i = 0; i <= n; i++) dp[i][0] = 1;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            dp[i + 1][j + 1] += dp[i][j + 1];
            if (tar[j] == s[i]) dp[i + 1][j + 1] += dp[i][j];
        }
    }
    return dp[n][m];
}
int main() {
    std::ios_base::sync_with_stdio(false);
    std::cin.tie(nullptr);
    cin >> n >> s;
    string t = "yukicoder";
    mint ans = solve(t);
    for (int i = 0; i < t.size(); i++) {
        char y = t[i];
        t[i] = '?';
        ans += solve(t);
        t[i] = y;
    }
    cout << ans.val() << "\n";
}