#include <bits/stdc++.h>
using namespace std;
#define overload3(_NULL, _1, _2, name, ...) name
#define rep1(i, n) for (remove_const_t<remove_reference_t<decltype(n)>> i = 0; i < (n); i++)
#define rep2(i, a, b) for (remove_const_t<remove_reference_t<decltype(b)>> i = a; i < (b); i++)
#define rep(...) overload3(__VA_ARGS__, rep2, rep1)(__VA_ARGS__)
#if __has_include(<debug.hpp>)
#    include <debug.hpp>
#else
#    define dbg(...) (void(0))
#endif
template<class T> void drop(const T &x) {
    cout << x << "\n";
    exit(0);
}
template<class T> bool chmax(T &a, const T &b) { return a < b and (a = b, true); }
template<class T> bool chmin(T &a, const T &b) { return a > b and (a = b, true); }
using i64 = long long;
using usize = size_t;

#include <atcoder/modint>
using mint = atcoder::modint1000000007;

mint solve(const string &s, const string &t) {
    const usize n = size(s);
    vector dp(n + 1, vector<mint>(size(t) + 1, 0));
    dp[0][0] = 1;
    rep(i, n) rep(j, size(t)) {
        dp[i + 1][j] += dp[i][j];
        if (s[i] == t[j]) dp[i + 1][j + 1] += dp[i][j];
    }
    mint ans = 0;
    for (usize i = 0; i <= n; i++) ans += dp[i].back();
    return ans;
}

int main() {
    usize n;
    cin >> n;
    string s;
    cin >> s;
    string t = "yukicoder";
    mint ans = solve(s, t);
    rep(i, 9) {
        string tmp = t;
        tmp[i] = '?';
        ans += solve(s, tmp);
    }
    cout << ans.val() << "\n";
}

struct IOSetup {
    IOSetup() noexcept {
        ios::sync_with_stdio(false);
        cin.tie(nullptr);
        cout << std::fixed << std::setprecision(10);
        cerr << std::fixed << std::setprecision(10);
    }
} iosetup;