#include <iostream>
#include <algorithm>
int main(void){
    int a[3]={};
    char ch;
    while((ch=getchar())!=EOF){
        if(ch=='t') a[0]++;
        if(ch=='r') a[1]++;
        if(ch=='e') a[2]++;
    }
    a[2]/=2;
    std::sort(a,a+3);
    std::cout<<a[0]<<"\n";
    return 0;
}