#include "bits/stdc++.h"
//#include "atcoder/all"
using namespace std;
//using namespace atcoder;
//using mint = modint1000000007;
//const int mod = 1000000007;
//using mint = modint998244353;
//const int mod = 998244353;
//const int INF = 1e9;
//const long long LINF = 1e18;
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep2(i,l,r)for(int i=(l);i<(r);++i)
#define rrep(i, n) for (int i = (n-1); i >= 0; --i)
#define rrep2(i,l,r)for(int i=(r-1);i>=(l);--i)
#define all(x) (x).begin(),(x).end()
#define allR(x) (x).rbegin(),(x).rend()
#define endl "\n"
long long maxdp[200005];
long long mindp[200005];
int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int N;
	string S;
	cin >> N >> S;
	vector<int>A(N);
	rep(i, N) {
		cin >> A[i];
		if (S[i] == 'B') { A[i] = -A[i]; }
	}
	maxdp[0] = 0;
	mindp[0] = 0;
	long long ans = 0;
	rep(i, N) {
		maxdp[i + 1] = max(maxdp[i] + A[i], (long long)0);
		mindp[i + 1] = min(mindp[i] + A[i], (long long)0);
		ans = max(ans, abs(maxdp[i + 1]));
		ans = max(ans, abs(mindp[i + 1]));
	}
	cout << ans << endl;
	return 0;
}