#include "bits/stdc++.h"

#define int long long

using namespace std;
using ll = long long;
using P = pair<ll, ll>;
const ll INF = (1LL << 61);
ll mod = 1000000007;

struct mint {
	ll x; // typedef long long ll;
	mint(ll x = 0) :x((x%mod + mod) % mod) {}
	mint operator-() const { return mint(-x); }
	mint& operator+=(const mint a) {
		if ((x += a.x) >= mod) x -= mod;
		return *this;
	}
	mint& operator-=(const mint a) {
		if ((x += mod - a.x) >= mod) x -= mod;
		return *this;
	}
	mint& operator*=(const mint a) {
		(x *= a.x) %= mod;
		return *this;
	}
	mint operator+(const mint a) const {
		mint res(*this);
		return res += a;
	}
	mint operator-(const mint a) const {
		mint res(*this);
		return res -= a;
	}
	mint operator*(const mint a) const {
		mint res(*this);
		return res *= a;
	}
	mint pow(ll t) const {
		if (!t) return 1;
		mint a = pow(t >> 1);
		a *= a;
		if (t & 1) a *= *this;
		return a;
	}

	// for prime mod
	mint inv() const {
		return pow(mod - 2);
	}
	mint& operator/=(const mint a) {
		return (*this) *= a.inv();
	}
	mint operator/(const mint a) const {
		mint res(*this);
		return res /= a;
	}
};
istream& operator>>(istream& is, mint& a) { return is >> a.x; }
ostream& operator<<(ostream& os, const mint& a) { return os << a.x; }
mint dp[100010][10];
signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	int N; cin >> N;
	string S; cin >> S;
	string T = "yukicoder";
	string tmp = T;
	mint ans = 0;
	for (int i = 0; i < 10; i++) {
		if (i != 10) {
			T[i] = '?';
		}
		for (int j = 0; j < 100010; j++)for (int k = 0; k < 10; k++)dp[j][k] = 0;
		dp[0][0] = 1;
		for (int j = 0; j < N; j++) {
			for (int k = 0; k < 10; k++) {
				dp[j + 1][k] += dp[j][k];
				if (k < 9 && T[k] == S[j]) {
					dp[j + 1][k + 1] += dp[j][k];
				}
			}
		}
		ans += dp[N][9];
		T = tmp;
	}
	cout << ans << endl;
	return 0;
}