#include<bits/stdc++.h>
#include<atcoder/all>
using namespace std;
using namespace atcoder;
#define rep(i,n)for (int i = 0; i < int(n); ++i)
#define rrep(i,n)for (int i = int(n)-1; i >= 0; --i)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
template<class T> void chmax(T& a, const T& b) {a = max(a, b);}
template<class T> void chmin(T& a, const T& b) {a = min(a, b);}
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;
using mint = modint1000000007;

const string yuki = "yukicoder";

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n;
    cin >> n;
    string s;
    cin >> s;
    mint dp[yuki.size() + 1][2] = {};
    dp[0][0] = 1;
    for(char c: s) {
        rrep(j, yuki.size()) rep(k, 2) {
            if (c == '?') {
                if (k) continue;
                dp[j + 1][1] += dp[j][0];
            } else if (yuki[j] == c) {
                dp[j + 1][k] +=dp[j][k];
            }
        }
    }
    mint ans;
    rep(k, 2) ans += dp[yuki.size()][k];
    cout << ans.val() << endl;
}