#include <iostream>
using namespace std;

int main() {
    string s;cin>>s;
    int ans = 0;
    if(s[0] != 'w') ans++;
    if(s[1] != 'h') ans++;
    if(s[2] != 'i') ans++;
    if(s[3] != 'l') ans++;
    if(s[4] != 'e') ans++;
    cout<<ans<<endl;
}
// 64 位输出请用 printf("%lld")