#include <bits/stdc++.h>

using namespace std;
const int N = 1e5+5;
typedef long long ll;
int n, dp[N][2], s[N][2], r[N];
char str[N];
ll ans; 

int main () {
	freopen("leaders.in", "r", stdin);
	freopen("leaders.out", "w", stdout);
	scanf("%d%s", &n, str+1);
	for (int i = 1;i <= n;i++) scanf("%d", &r[i]);
	for (int i = 1;i <= n;i++) {
		s[i][0] = s[i-1][0];
		s[i][1] = s[i-1][1];
		if (str[i] == 'G') s[i][0]++;
		else s[i][1]++;
	}
	for (int i = n;i >= 1;i--) {
		int op = str[i]=='G'?0:1;
		dp[i][0] = dp[i+1][0];
		dp[i][1] = dp[i+1][1];
		if (s[r[i]][op]-s[i-1][op]==s[n][op]) {
			ans += dp[i+1][op^1]; dp[i][op]++;
		}
		else ans += dp[i+1][op^1]-dp[r[i]+1][op^1];
//		cout << ans << " " << dp[i][0] << " " << dp[i][1] << endl;
	}
	printf("%lld\n", ans);
	return 0;
}