#include <bits/stdc++.h>

#include <atcoder/string>
using namespace std;
using namespace atcoder;
void fast_io() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
}

int main() {
    fast_io();
    int n;
    cin >> n;
    vector<int> a(n);
    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }
    string s;
    cin >> s;
    string t = "";
    for (int i = 0; i < n; i++) {
        if (a[i] < a[(i + 1) % n]) {
            t += "<";
        } else {
            t += ">";
        }
    }
    t += t;
    auto z = z_algorithm(s + t);
    for (int i = 0; i < n; i++) {
        if (z[i + n - 1] >= n - 1) {
            cout << i << endl;
            return 0;
        }
    }
    cout << -1 << endl;
}