#include <bits/stdc++.h>
//eolibraries
#define lnf 3999999999999999999
#define inf 999999999
#define fi first
#define se second
#define pb push_back
#define all(c) (c).begin(),(c).end()
#define sz(c) (int)(c).size()
#define make_unique(a) sort(all(a)),a.erase(unique(all(a)),a.end());
#define rep(i,n) for(int i=0;i<n;i++)
#define drep(i,n) for(int i=n-1;i>=0;i--)
#define crep(i,x,n) for(int i=x;i<n;i++)
#define vec(...) vector<__VA_ARGS__>
#define _3ioVv0Q ios_base::sync_with_stdio(false),cin.tie(0),cout.tie(0)
//eodefine
using namespace std;
typedef long long i64;
typedef long double ld;
using pii=pair<int,int>;
using tpii=pair<int,pii>;
using vi=vec(i64);
const int mxn=12000;
const int mod=1e9+7;
//snuke's modular int
// template <i64 mod>
struct modularint{
	i64 x;
	modularint(i64 x=0):x(x%mod){}
	modularint& operator+=(const modularint a){
		if ((x += a.x) >= mod) x -= mod;
		return *this;
	}
	modularint& operator-=(const modularint a){
		if ((x += mod-a.x) >= mod) x -= mod;
		return *this;
	}
	modularint& operator*=(const modularint a){
		(x *= a.x) %= mod;
		return *this;
	}
	modularint operator+(const modularint a)const{
		modularint res(*this);
		return res+=a;
	}
	modularint operator-(const modularint a)const{
		modularint res(*this);
		return res-=a;
	}
	modularint operator*(const modularint a)const{
		modularint res(*this);
		return res*=a;
	}
	modularint pow(i64 n)const{
		modularint res=1,x(*this);
		while(n){
			if(n&1)res*=x;
			x*=x;
			n>>=1;
		}
		return res;
	}
	modularint inv()const{
		return pow(mod-2);
	}
};

using mint=modularint;

int main(){
_3ioVv0Q;
	int n;
	string s;
	cin>>n;
	cin>>s;
	string yuki="yukicoder";
	int m=sz(yuki);
	// cout<<m<<"\n";
	// vec(vec(mint)) dp(n+1,vec(mint)(m+1));
	vec(vec(vec(mint))) dp(n+1,vec(vec(mint))(m+1,vec(mint)(2,0)));
	dp[0][0][0]=1;
	rep(i,n){
		rep(j,m+1){
			rep(t,2) dp[i+1][j][t]+=dp[i][j][t];
		}
		if(s[i]=='?'){
			rep(j,m){
				dp[i+1][j+1][1]+=dp[i][j][0];
			}
		}else{
			int _j=-inf;
			rep(j,m){
				if(s[i]==yuki[j]){
					_j=j;
					break;
				}
			}
			if(_j==-inf) continue;
			rep(t,2){
				dp[i+1][_j+1][t]+=dp[i][_j][t];
			}
		}
	}
	dp[n][m][0]+=dp[n][m][1];
	cout<<dp[n][m][0].x<<"\n";
//	
	return 0;
}