#include <iostream>
#include <string>

using namespace std;
int main()
{
	int a=0, b=0, c=0;
	string str;
	cin >> str;
	for (int i = 0; i < str.length(); i++)
	{
		if (str[i] == 't' || str[i]=='r')
		{
			a++;
		}
		if (str[i] == 'e')
		{
			b++;
		}

		if (a == 2 && b == 2)
		{
			c++;
			a = 0, b = 0;
		}
	}

	cout << c << endl;
	return 0;
}