#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define srep(i,s,t) for (int i = s; i < t; ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
using namespace std;
typedef long long int ll;
typedef pair<int,int> P;
#define yn {puts("YES");}else{puts("NO");}
#define MAX_N 200005

int main() {
    int n; cin >> n;
    string s; cin >> s;
    ll a[n] = {};
    rep(i,n) cin >> a[i];
    ll ans = 0;
    rep(i,n){
        if(s[i] == 'B') a[i] *= -1;
    }
    ll now = 0;
    rep(i,n){
        now = max(now+a[i],a[i]);
        ans = max(ans, now);
    }
    rep(i,n) a[i] *= -1;
    now = 0;
    rep(i,n){
        now = max(now+a[i],a[i]);
        ans = max(ans, now);
    }
    cout << ans << endl;
    return 0;
}