#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); i++)
using namespace std;
typedef long long ll;

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    
    int N; string S; cin >> N >> S;
    vector<ll> a(N);
    rep(i,N) {
        cin >> a[i];
        if(S[i] == 'B') a[i] *= -1;
    }

    vector<ll> a_sum(N + 1, 0);
    rep(i,N) a_sum[i + 1] += a_sum[i] + a[i];

    ll mi = 0, ma = 0, ans = 0;
    rep(i,N+1) {
        ans = max({ans, abs(mi - a_sum[i]), abs(ma - a_sum[i])});
        mi = min(mi, a_sum[i]);
        ma = max(ma, a_sum[i]);
    }
    cout << ans << endl;
}