#include <stdio.h>
#include <algorithm>
#include <iostream>
#include <string>
#include <vector>
#include <functional>
#include <map>
#include <iomanip>
#include <math.h> 
#include <stack>
#include <queue>
#include <bitset>
#include <cstdlib>
#include <tuple>
#include <cctype>
#include <ctype.h>
#include <set>
#include <sstream>

using namespace std;


int main() {
	int i, j, k;
	string s;
	
	cin >> s;

	int t = 0, r = 0, e = 0;

	for (i = 0; i < s.length(); i++) {
		if (s[i] == 't') {
			t++;
		}
		else if (s[i] == 'r') {
			r++;
		}
		else if (s[i] == 'e') {
			e++;
		}
	}


	e /= 2;

	int minn = 99999999;
	if (t >= 1 && r >= 1 && e >= 1) {
		minn = min({ t,r,e });
		cout << minn << endl;
	}
	else {
		cout << 0 << endl;
		
	}




	getchar();
	getchar();
	return 0;
}