#include <bits/stdc++.h>

using namespace std;

#define int long long

const int MOD = 1e9 + 7;

vector<int> prefix_function(const string s) {
    int n = s.size();
    vector<int> pi(n);
    for (int i = 1; i < n; i++) {
        int j = pi[i - 1];
        while (j > 0 && s[i] != s[j]) j = pi[j - 1];
        if (s[i] == s[j]) j++;
        pi[i] = j;
    }
    return pi;
}

int mul(int a, int b) {
    a %= MOD; b %= MOD;
    return a * b % MOD;
}

signed main() {
    ios_base::sync_with_stdio(false); cin.tie(0);

    int k;
    string s;
    cin >> k >> s;
    int n = s.size();

    vector<int> pi = prefix_function(s);
    int t = n - pi[n - 1];
    if (n % t == 0) {
        k *= n / t;
        n = t;
        s = s.substr(0, n);
    }

    pi = prefix_function(s + s);
    int result = 0;
    for (int i = 0; i < n; i++) {
        result += pi[i];
        result %= MOD;
    }

    if (k == 1) {
        cout << result << '\n';
        return 0;
    }

    for (int i = n; i < 2 * n; i++) {
        result += pi[i];
        result %= MOD;
    }

    t = mul((mul(k - 1, n) + 1), mul(k - 1, n)) - mul(n + 1, n);
    t = t * 500000004 % MOD;
    result += t;
    result %= MOD;
    if (result < 0) result += MOD;

    cout << result << '\n';
}