#include<stdio.h>
char S[1000001];
main(){
    int count[] = {0,0,0};
    scanf("%s",S);
    for(int i = 0;S[i] != '\0';i++){
        if(S[i] == 't'){
            count[0] ++;
        }else if(S[i] == 'r'){
            count[1] ++;
        }else if(S[i] == 'e'){
            count[2] ++;
        }
    }
    count[2] /= 2;
    int min = 1000000;
    for(int i = 0;i < 3;i++){
        if(count[i] < min){
            min = count[i];
        }
    }
    printf("%d\n",min);
}