#include <iostream>
#include <vector>
#include <functional>
#include <chrono>
#include <random>
#include <map>

using namespace std;

const int N = 2e6 + 3;

int n, prefix[N], a[N];
string s;

int get_sum(int l, int r){
    return prefix[r] - prefix[l - 1];
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(NULL);

    cin >> n >> s;
    for(int i = 1; i <= 2 * n - 1; ++i){
        a[i] = s[i] == 'W';
        prefix[i] = prefix[i - 1] + a[i];
    }

    map<int, int> mp;
    mt19937 mt(3);
    for(int i = 1; i <= 4 * n; ++i){
        int l = mt() % s.size() + 1;
        int r = mt() % s.size() + 1;
        if(l > r) swap(l, r);

        if(r - l + 1 < n){
            --i;
            continue;
        }

        mp[get_sum(l, r)]++;
    }

    vector<pair<int, int>> v(mp.begin(), mp.end());
    sort(v.begin(), v.end(), [&](auto l, auto r){
        return l.second > r.second;
    });

    cout << v[0].first << "\n";
}