#include <bits/stdc++.h>
#include <atcoder/modint>
using namespace std;
using namespace atcoder;
//using mint = modint998244353;
using mint = modint1000000007;
using ll = long long;
using ld = long double;
using pll = pair<ll, ll>;
using tlll = tuple<ll, ll, ll>;
constexpr ll INF = 1LL << 60;
template<class T> bool chmin(T& a, T b) {if (a > b) {a = b; return true;} return false;}
template<class T> bool chmax(T& a, T b) {if (a < b) {a = b; return true;} return false;}
ll safemod(ll A, ll M) {return (A % M + M) % M;}
ll divfloor(ll A, ll B) {if (B < 0) {return divfloor(-A, -B);} return (A - safemod(A, B)) / B;}
ll divceil(ll A, ll B) {if (B < 0) {return divceil(-A, -B);} return divfloor(A + B - 1, B);}
#define FINALANS(A) do {cout << (A) << '\n'; exit(0);} while (false)

int main()
{
  ll N;
  string S;
  cin >> N >> S;

  const string T = "yukicoder";
  const ll M = T.size();
  vector dp(N + 1, vector(M + 1, vector(2, mint(0))));
  dp.at(0).at(0).at(0) = 1;
  for (ll i = 0; i < N; i++)
  {
    for (ll j = 0; j <= M; j++)
    {
      for (ll b = 0; b < 2; b++)
      {
        if (j < M && S.at(i) == T.at(j))
          dp.at(i + 1).at(j + 1).at(b) += dp.at(i).at(j).at(b);
        if (j < M && b == 0 && S.at(i) == '?')
          dp.at(i + 1).at(j + 1).at(1) += dp.at(i).at(j).at(b);
        dp.at(i + 1).at(j).at(b) += dp.at(i).at(j).at(b);
      }
    }
  }

  mint ans = dp.at(N).at(M).at(0) + dp.at(N).at(M).at(1);
  cout << ans.val() << endl;
}