#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
typedef long long int ll;
typedef long double ld;
#define FOR(i,l,r) for(ll i=l;i<r;i++)
#define REP(i,n) FOR(i,0,n)
#define RFOR(i,l,r) for(ll i=r-1;i>=l;i--)
#define RREP(i,n) RFOR(i,0,n)
#define ALL(x) x.begin(),x.end()
#define P pair<ll,ll>
#define F first
#define S second
#define BS(A,x) binary_search(ALL(A),x)
#define LB(A,x) (ll)(lower_bound(ALL(A),x)-A.begin())
#define UB(A,x) (ll)(upper_bound(ALL(A),x)-A.begin())
#define COU(A,x) UB(A,x)-LB(A,x)
template<typename T>using min_priority_queue=priority_queue<T,vector<T>,greater<T>>;
using mint=modint1000000007;
//using mint=modint998244353;
signed main(){
  ll N;string S;cin>>N>>S;
  mint ans=0;
  REP(i,10){
    string T="yukicoder";
    if(i<9)T[i]='?';
    vector<mint>DP(8);
    REP(j,N)REP(k,9)if(S[j]==T[k]){
      if(k==0)DP[k]++;
      else if(k<8)DP[k]+=DP[k-1];
      else ans+=DP[7];
    }
  }
  cout<<ans.val()<<endl;
  return 0;
}