#include <iostream>
#include <string>
#include <vector>
using namespace std;

#include <atcoder/modint>
using mint = atcoder::modint1000000007;

int main() {
    int N;
    string S;
    cin >> N >> S;
    const string T = "yukicoder";
    vector dp(2, vector<mint>(T.size() + 1));
    dp[0][0] = 1;
    for (auto c : S) {
        if (c == '?') {
            for (int i = 0; i < int(T.size()); ++i) dp[1][i + 1] += dp[0][i];
        } else {
            for (int d = int(T.size()) - 1; d >= 0; --d) {
                if (T[d] == c) {
                    for (int e = 0; e < 2; ++e) dp[e][d + 1] += dp[e][d];
                }
            }
        }
    }
    cout << (dp[0].back() + dp[1].back()).val() << '\n';
}