#include<bits/stdc++.h>
using namespace std;
char s[10010];
int main(){
cin >> s;
int sum = 0;
for(int i = 0; s[i]; i++){
if(s[i] >= '0' && s[i] <= '9') sum += s[i] - '0';
}
cout << sum << endl;
return 0;
}