#include <iostream>
#include <cstdio>
#include <string>
#include <algorithm>
#include <utility>
#include <cmath>
#include <vector>
#include <stack>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <tuple>
#include <numeric>
#include <functional>
using namespace std;
typedef long long ll;
typedef vector<ll> vl;
typedef vector<vector<ll>> vvl;
typedef pair<ll, ll> P;
#define rep(i, n) for(ll i = 0; i < n; i++)
#define exrep(i, a, b) for(ll i = a; i <= b; i++)
#define out(x) cout << x << endl
#define exout(x) printf("%.10f\n", x)
#define chmax(x, y) x = max(x, y)
#define chmin(x, y) x = min(x, y)
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define pb push_back
#define re0 return 0
const ll mod = 1000000007;
const ll INF = 1e16;
 
int main() {
    ll n;
    string s;
    cin >> n >> s;
    
    vl a(n);
    rep(i, n) {
        cin >> a[i];
        if(s[i] == 'B') {
            a[i] *= -1;
        }
    }
 
    ll ans1 = -INF;
    ll ans2 = INF;
    ll x1 = 0;
    ll x2 = 0;
    rep(i, n) {
        x1 += a[i];
        x2 += a[i];
        chmax(ans1, x1);
        chmin(ans2, x2);
        if(x1 < 0) {
            x1 = 0;
        }
        if(x2 > 0) {
            x2 = 0;
        }
    }
 
    out(max(ans1, -ans2));
    re0;
}