#include <stdio.h>
int main(void){
	char str[10000000];
	scanf("%s",str);
	
	int count[3];
	for(int i = 0;i < 10000000;i++){
		if(str[i] == 't'){
			count[0]++;
		}else if(str[i] == 'r'){
			count[1]++;
		}else if(str[i] == 'e'){
			count[2]++;
		}
	}
	count[2] /= 2;
	// ソート
	for(int i = 0;i < 3;i++){
		for(int j = 0;j < 3;j++){
			if(count[i] > count[j]){
				int tmp = count[i];
				count[i] = count[j];
				count[j] = tmp;
			}
		}
	}
	printf("%d",count[2]);
}