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

#define ll long long
#define rep(i, n) for (int i = 0; i < (n); i++)
#define P pair<int, int>

const ll INF = 1e18;
int main() {
  int n;
  string s;
  cin >> n >> s;
  vector<ll> x(n), sum(n+1), mx(n+1), mn(n+1);
  rep(i, n) {
    cin >> x[i];
    if (s[i] == 'B') x[i] *= -1;
  }
  rep(i, n) sum[i+1] = sum[i] + x[i];
  rep(i, n) {
    mx[i+1] = max(mx[i], sum[i+1]);
    mn[i+1] = min(mn[i], sum[i+1]);
  }
  ll ans = -1e18;
  for (int i = 1; i <= n; i++) {
    ans = max(ans, sum[i]-mn[i]);
    ans = max(ans, abs(sum[i]-mx[i]));
  }
  cout << ans << endl;



}