#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;
string ch;
void back(int k) {
	for(int i = k; i < k + 6; i ++) {
		ch[i] = 0;
	}
}
int main() {
	getline(cin,ch);
	int answer = 0;
	int b = -1;
	while(true) {
		int a = ch.find("friend");
		if(a == -1) {
			break;
		}
		back(a);
		if(b != -1 && (a - (b + 5)) < 4) {
			a = -1;
		} else {
			answer ++;
			b = a;
		}
	}
	cout << answer;
	return 0;
}

玄关