#include <iostream>
#include <vector>
#include <string>
#include <algorithm>

#define rep(i, a, n) for (int i = (int)(a); i < (int)(n); i++)

using i64 = std::int64_t;

template <class T>
inline bool chmax(T &a, T b){
    if (a < b){
        a = b;
        return true;
    }
    return false;
}

int main() {
	int n;
	std::string s;
	std::cin >> n >> s;
	std::vector<i64> a(n);
	std::vector<i64> sum(n+1,0);
	std::vector<i64> max(n+1,0), min(n+1,0);
	rep(i,0,n) {
		std::cin >> a[i];
		if(s[i] == 'B') a[i] *= -1;
		sum[i+1] = sum[i] + a[i];
		max[i+1] = std::max(max[i], sum[i]);
		min[i+1] = std::min(min[i], sum[i]);
	}
	i64 ans = -1;
	rep(i,0,n) {
		chmax(ans, std::abs(sum[i+1]-max[i+1]));
		chmax(ans, std::abs(sum[i+1]-min[i+1]));
	}
	std::cout << ans << '\n';
}