#include <algorithm>
#include <cstdio>
#include <iostream>
#include <map>
#include <cmath>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
#include <stdlib.h>
#include <stdio.h>
#include <bitset>
using namespace std;

#define ll         long long
#define PI         acos(-1.0)
#define FOR(I,A,B) for(int I = (A); I < (B); ++I)

int main(){
    string s;
    getline(cin, s);

    int ans = 0;
    FOR(i, 0, s.length()){
        int x = s[i] - '0';
        if(x>=0 && x<=9) ans += x;
    }
    cout << ans << endl;
}