#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
//constexpr ll MOD = 1e9 + 7;
constexpr ll MOD = 998244353;
//constexpr ll MOD = ;
ll mod(ll A, ll M) {return (A % M + M) % M;}
constexpr ll INF = 1LL << 60;
template<class T> bool chmin(T& a, T b) {if (a > b) {a = b; return true;} return false;}
template<class T> bool chmax(T& a, T b) {if (a < b) {a = b; return true;} return false;}
ll divceil(ll A, ll B) {return (A + (B - 1)) / B;}
#define FINALANS(A) do {cout << (A) << '\n'; exit(0);} while (false)

int main()
{
  ll N;
  cin >> N;
  string S;
  cin >> S;
  vector<ll> A(N);
  for (ll i = 0; i < N; i++)
  {
    cin >> A.at(i);
  }

  vector<ll> acA(N + 1, 0);
  for (ll i = 0; i < N; i++)
  {
    acA.at(i + 1) = acA.at(i) + ((S.at(i) == 'R') ? 1 : -1) * A.at(i);
  }

  ll M = *max_element(acA.begin(), acA.end());
  ll m = *min_element(acA.begin(), acA.end());
  ll ans = M - m;

  cout << ans << endl;
}