#include <bits/stdc++.h>
using namespace std;

const int mod = 1000000007;

template< int mod >
struct ModInt {
    int x;

    ModInt() : x(0) {}

    ModInt(int64_t y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {}

    ModInt &operator+=(const ModInt &p) {
        if ((x += p.x) >= mod) x -= mod;
        return *this;
    }

    ModInt &operator-=(const ModInt &p) {
        if ((x += mod - p.x) >= mod) x -= mod;
        return *this;
    }

    ModInt &operator*=(const ModInt &p) {
        x = (int) (1LL * x * p.x % mod);
        return *this;
    }

    ModInt &operator/=(const ModInt &p) {
        *this *= p.inverse();
        return *this;
    }

  ModInt operator-() const { return ModInt(-x); }

  ModInt operator+(const ModInt &p) const { return ModInt(*this) += p; }

  ModInt operator-(const ModInt &p) const { return ModInt(*this) -= p; }

  ModInt operator*(const ModInt &p) const { return ModInt(*this) *= p; }

  ModInt operator/(const ModInt &p) const { return ModInt(*this) /= p; }

  bool operator==(const ModInt &p) const { return x == p.x; }

  bool operator!=(const ModInt &p) const { return x != p.x; }

    ModInt inverse() const {
        int a = x, b = mod, u = 1, v = 0, t;
        while (b > 0) {
            t = a / b;
            swap(a -= t * b, b);
            swap(u -= t * v, v);
        }
        return ModInt(u);
    }

    ModInt pow(int64_t n) const {
        ModInt ret(1), mul(x);
            while (n > 0) {
            if (n & 1) ret *= mul;
            mul *= mul;
            n >>= 1;
        }
        return ret;
    }

    friend ostream &operator<<(ostream &os, const ModInt &p) {
        return os << p.x;
    }

    friend istream &operator>>(istream &is, ModInt &a) {
        int64_t t;
        is >> t;
        a = ModInt< mod >(t);
        return (is);
    }

    static int get_mod() { return mod; }
};

using mint = ModInt< mod >;

string yuki = "yukicoder";

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

    int M = yuki.size();
    vector<vector<vector<mint>>> dp(N+1, vector<vector<mint>>(M+1, vector<mint>(2, 0)));
    dp[0][0][0] = 1;
    for (int i = 0; i < N; i++) {
        for (int j = 0; j <= M; j++) for (int k = 0; k < 2; k++) dp[i+1][j][k] += dp[i][j][k];
        for (int j = 0; j < M; j++) {
            for (int k = 0; k < 2; k++) {
                if (S[i] == yuki[j]) {
                    dp[i+1][j+1][k] += dp[i][j][k];
                }
                if (k == 0 && S[i] == '?') {
                    dp[i+1][j+1][k+1] += dp[i][j][k];
                }
            }
        }
    }

    cout << dp[N][M][0] + dp[N][M][1] << endl;
}