#include <bits/stdc++.h>
using namespace std;
int main()
{
    string s;
    getline(cin, s);
    int cnt = 0;
    for (int i = 1; i <= s.length(); i++)
    {
        if (s[i] <= '9' && s[i] >= '0')
            cnt++;
    }
    cout << cnt << endl;
    return 0;
}