#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#define _GLIBCXX_DEBUG
using namespace std;
using std::cout;
using std::cin;
using std::endl;
using ll=long long;
using ld=long double;
ll ILL=1167167167167167167;
const int INF=2100000000;
const ll mod=998244353;
#define rep(i,a) for (ll i=0;i<a;i++)
template<class T> using _pq = priority_queue<T, vector<T>, greater<T>>;
template<class T> ll LB(vector<T> &v,T a){return lower_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> ll UB(vector<T> &v,T a){return upper_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> bool chmin(T &a,const T &b){if(a>b){a=b;return 1;}else return 0;}
template<class T> bool chmax(T &a,const T &b){if(a<b){a=b;return 1;}else return 0;}
template<class T> void So(vector<T> &v) {sort(v.begin(),v.end());}
template<class T> void Sore(vector<T> &v) {sort(v.begin(),v.end(),[](T x,T y){return x>y;});}
void yneos(bool a){if(a) cout<<"Yes\n"; else cout<<"No\n";}


const int MAX_N=200000;

//  rainy ~ 雨に打たれて ~
int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);

	int N;
    cin>>N;
    assert(2<=N&&N<=MAX_N);
    vector<int> p(N),q(N);
	rep(i,N){
        int a;
        cin>>a;
        a--;
        assert(0<=a&&a<N);
        assert(q[a]==0);
        q[a]++;
        p[i]=a;
    }
    string S;
    cin>>S;
    assert(S.size()==(N-1));
    ll ans=0;
    ll base=1;
    ll tmp=0;
    rep(i,N-1){
        assert(S[i]=='>'||S[i]=='<');
        if(S[i]=='<') ans+=base;
        base*=2ll;
        base%=mod;
    }
    base=1;
    rep(i,N-1){
        if(p[i]<p[i+1]) tmp+=base;
        base*=2ll;
        base%=mod;
    }
    ans%=mod;
    tmp%=mod;
    rep(i,N){
        if(ans==tmp){
            cout<<i<<"\n";
            return 0;
        }
        if(p[(i+N-1)%N]<p[i%N]) tmp+=base;
        if(p[i]<p[(i+1)%N]) tmp--;
        if(tmp%2) tmp=(tmp+mod)/2;
        else tmp/=2;
        tmp=(tmp%mod+mod)%mod;
    }
    cout<<"-1\n";
}