#include <iostream>
#include <algorithm>
#include <vector>
#include<string>

using namespace std;
int main(){
	string s;
	cin >> s;
	vector<int> a(3);
	for (int i = 0; i < s.size(); i++) {
		if (s[i] == 't') {
			a[0]++;
		}else if (s[i] == 'r') {
			a[1]++;
		}else if(s[i]=='e'){
			a[2]++;
		}
	}
	a[2] /= 2;
	vector<int>::iterator itr = min_element(a.begin(), a.end());
	int minIndex = distance(a.begin(), itr);
	cout << a[minIndex] << endl;
	return 0;
}