#include <bits/stdc++.h>
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define repp(i,n,m) for (int i = m; i < (n); ++i)
using namespace std;
using ll = long long;
const ll inf = 1e18;

int main(){
    int n; cin >> n;
    string s; cin >> s;
    vector<ll> ar(n);
    rep(i,n) cin >> ar[i];
    rep(i,n) if (s[i] == 'B') ar[i] *= -1LL;
    vector<ll> rui(n+1,0LL);
    repp(i,n+1,1) rui[i] = rui[i-1] + ar[i-1];
    vector<ll> ma(n+1,0LL);
    repp(i,n+1,1) ma[i] = max(ma[i-1],rui[i]);
    vector<ll> mi(n+1,0LL);
    repp(i,n+1,1) mi[i] = min(mi[i-1],rui[i]);
    ll mans = -inf;
    repp(i,n+1,1){
        mans = max(mans,rui[i] - mi[i-1]);
    }
    ll mins = inf;
    repp(i,n+1,1){
        mins = min(mins,rui[i] - ma[i-1]);
    }
    cout << max(abs(mans),abs(mins)) << endl;
}