#include <bits/stdc++.h>
#include <vector>
#include <tuple>
#include <regex>
#include <string>
#include <stack>
#include <algorithm>
using namespace std;
//printf , scanfが使えるよ！！
/*
[問題メモ]


*/

int main() {
    //Let's algorithm!!
    char s[100] = {};
    int length = 0;
    int count_0 = 0;
    scanf("%s",&s);
    for(int i=0;i<100;i++){
        if(48 <= s[i] && s[i] <= 57){
            length++;
        }
        if(s[i] == 48){
            count_0++;
        }
    }
    printf("%d",length-count_0-1);
    return 0;
}