#include<iostream>
using namespace std;
int main(){
    string s;
    cin >> s;
    int times=0;
    if(s[0]!='w')times++;
    if(s[1]!='h')times++;
    if(s[2]!='i')times++;
    if(s[3]!='l')times++;
    if(s[4]!='e')times++;
    cout << times;
    return 0;
}