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

// 10
// RRBBRBBRBR
// 6 -7 0 8 -1 -2 6 4 -9 -1
// 6 -1 -1 7 6 4 10 14 5 4

    int
    main() {
    cin.tie(0);
    ios_base::sync_with_stdio(false);
    
    int n;
    string s;
    cin >> n >> s;
    vector<ll> a(n);
    rep(i, n) cin >> a[i];
    rep(i, n) if(s[i] == 'B') a[i] *= -1;
    vector<ll> sum(n + 1, 0);
    rep(i, n) sum[i + 1] = sum[i] + a[i];
    const ll INF = 1e18;
    ll ma = -INF, mi = INF;
    rep(i, n + 1) {
        ma = max(ma, sum[i]);
        mi = min(mi, sum[i]);
    }
    cout << ma - mi << endl;
    return 0;
}