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

#define rep(i, n) for(int i = 0; i < n; ++i)
#define REP(i, x, n) for(int i = (x); i < n; ++i)
#define rrep(i, n) for(int i = n - 1; i >= 0; --i)
#define RREP(i, x, n) for(int i = n - 1; i >= (x); --i)
#define all(x) x.begin(), x.end()
using ll = long long;
using vll = vector<ll>;
using vvll = vector<vll>;
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vvvvi = vector<vvvi>;
using vb = vector<bool>;
using vvb = vector<vb>;
using P = pair<int, int>;
using Pll = pair<ll, ll>;
using vp = vector<P>;
using vvp = vector<vp>;

template <class T> bool chmax(T &a, const T &b) {
    if(a < b) {
        a = b;
        return 1;
    }
    return 0;
}
template <class T> bool chmin(T &a, const T &b) {
    if(b < a) {
        a = b;
        return 1;
    }
    return 0;
}

template <typename T> vector<int> Zalgorithm(vector<T> S) {
    int n = S.size();
    vector<int> arr(n);
    arr[0] = n;
    int i = 1, j = 0;
    while(i < n) {
        while(i + j < n && S[j] == S[i + j]) ++j;
        arr[i] = j;
        if(j == 0) {
            ++i;
            continue;
        }
        int k = 1;
        while(i + k < n && k + arr[k] < j) {
            arr[i + k] = arr[k];
            ++k;
        }
        i += k;
        j -= k;
    }
    return arr;
}

void solve() {
    int n;
    cin >> n;
    vi a(n);
    rep(i, n) cin >> a[i];
    string s;
    cin >> s;

    string t;
    rep(i, 2 * n - 2) t += (a[(i) % n] < a[(i + 1) % n] ? '<' : '>');

    vector<char> u;
    for(char &e : s) u.push_back(e);
    for(char &e : t) u.push_back(e);
    for(char &e : t) u.push_back(e);

    --n;
    auto z = Zalgorithm(u);

    REP(i, n, 3 * n) {
        if(z[i] >= n) {
            cout << i - n << endl;
            return;
        }
    }
    cout << -1 << endl;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);

    int t = 1;
    // cin >> t;

    while(t--) solve();

    return 0;
}