#include <bits/stdc++.h>
using namespace std;
int main(){
	int cnt = 0;
    string s;
    cin >> s;
    int n = s.size();
    for(int i = 0; i < n; i ++){
    	if(i == 0 and s[i] != 'w') cnt ++;
    	if(i == 1 and s[i] != 'h') cnt ++;
    	if(i == 2 and s[i] != 'i') cnt ++;
    	if(i == 3 and s[i] != 'l') cnt ++;
    	if(i == 4 and s[i] != 'e') cnt ++;
	}
	cout << cnt;
    return 0;
}