#include <iostream>
#include<algorithm>
#include<climits>
#include <stdexcept>
using namespace std;
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n;
cin >> n;
string s;
cin >> s;
int left = 0;
int length = 0;
int tmplen = 0;
int check = 0;
for (int right = 0; right < n;) {
if ((s[right] == 'a' && check == 2) || (s[right] == 'a' && check == 0)) {
tmplen++;
right++;
check = 1;
length = max(length, tmplen);
}
else if ((s[right] == 'h' && check == 1) || (s[right] == 'h' && check == 0)) {
tmplen++;
right++;
check = 2;
length = max(length, tmplen);
}
else {
if (s[right] == 'a') {
tmplen = 1;
left = right;
right++;
check = 1;
}
else if (s[right] == 'h') {
tmplen = 1;
left = right;
right++;
check = 2;
}
else {
tmplen = 0;
left = right;
right++;
check = 0;
}
}
}
cout << length << '\n';
}
// 64 位输出请用 printf("%lld")