#include <cwctype>
#include <iostream>
#include <string>
#include <sstream>
using namespace std;

int main() {

	string s;
	cin >> s;

	int f,r,e=0;

	for(int i=0; i<s.length();i++){
		if(s[i] == 'f'){
			f++;
		}
		if(s[i] == 'r'){
			r++;
		}
		if(s[i] == 'e'){
			e++;
		}
	}

	int  min1 = min(f,r);

	int ans = min(min1,e/2);

	cout<<ans<<endl;

	return 0;
}