#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint1000000007;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf 1000000000

int main(){
	
	int n;
	cin>>n;
	
	string s;
	cin>>s;
	
	string t = "yukicoder";
	
	vector dp(t.size()+1,vector<mint>(2,0));
	dp[0][0] = 1;
	
	rep(i,s.size()){
		vector ndp(t.size()+1,vector<mint>(2,0));
		
		rep(j,t.size()+1){
			rep(k,2){
				ndp[j][k]+=dp[j][k];
				if(j!=t.size()){
					if(s[i]==t[j]){
						ndp[j+1][k] += dp[j][k];
					}
					if(s[i]=='?'&&k==0){
						ndp[j+1][k+1] += dp[j][k];
					}
					
				}
				
			}
		}
		swap(dp,ndp);
	}
	
	mint ans = 0;
	rep(i,2)ans += dp.back()[i];
	cout<<ans.val()<<endl;
	return 0;
}