#include<bits/stdc++.h>
using namespace std;

int main() {
    string s;
    cin >> s;
    map<int, int> p;
    p['0'] = p['6'] = p['9'] = 1;
    p['8'] = 2;
  //直接用map映射记录答案即可
    int ans = 0;
    for (char c: s) {
        ans += p[c];
    }
    cout << ans << endl;
}

//直接用map映射记录答案即可