#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using mint = modint1000000007;
const int mod = 1000000007;
//using mint = modint998244353;
//const int mod = 998244353;
//const int INF = 1e9;
//const long long LINF = 1e18;
//const bool debug = false;
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep2(i,l,r)for(int i=(l);i<(r);++i)
#define rrep(i, n) for (int i = (n-1); i >= 0; --i)
#define rrep2(i,l,r)for(int i=(r-1);i>=(l);--i)
#define all(x) (x).begin(),(x).end()
#define allR(x) (x).rbegin(),(x).rend()
#define endl "\n"
#define P pair<int,int>
template<typename A, typename B> inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; }
template<typename A, typename B> inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; }

int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int n; cin >> n;
	string s; cin >> s;
	string yuki = "yukicoder";
	mint ans = 0;
	rep(i, 10) {
		string y = yuki;
		if (0 != i)y[i - 1] = '?';
		vector<vector<mint>> dp(n + 1, vector<mint>(10));
		dp[0][0] = 1;
		rep(j, n) {
			rep(k, y.size()) {
				dp[j + 1][k] += dp[j][k];
				if (y[k] == s[j])dp[j + 1][k + 1] += dp[j][k];
			}
		}
		ans += dp[n][9];
	}
	cout << ans.val() << endl;
	return 0;
}