#include <iostream>
#include <string>
using namespace std;
const int N = 505;
string str;
int cnt1, cnt2, n, k, res;
inline int min(int l, int r){return l > r ? r : l;}
inline int max(int l, int r){return l > r ? l : r;}
int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0), cout.tie(0);
	cin >> n >> k >> str;
	for(int i = 0; i < n; i++){
		if(str[i] == 'j') cnt1++;
		if(str[i - 1] == 'j' && str[i] == 'z' && i) res++;
	}
	cnt2 = n - cnt1;
	res = max(res, min(cnt1, min(cnt2, res + k)));
	cout << res;
	return 0;
}