#include<map>
#include<iostream>
#include<vector>
#include<iomanip>
#include<random>
#include<cmath>
#include<set>
using namespace std;
int n; vector<int>ans(3000005,0);
int main() {
	cin >> n;
	string a;
	cin >> a;
	int lk = 0;
	for (int i = n; i <= 2 * n - 1; i++) {
		int pp = 0, la = 0, l = 0;
		for (int p = 0; p <=2 * n-1-i; p++) {
			if (!pp) {
				pp = 1;
				string k = a.substr(p, i);
				for (int j = 0; j < i; j++) {
					if (k[j] == 'W')l++;
				}
			}
			else {
				if (a[la] == 'W')l--;
				if (a[la + i] == 'W')l++;
			}
			la = p;
			ans[l]++;
			if (ans[l] == n) {
				cout <<l<<endl;
				return 0;
			}
		}
	}
}