#include <iostream>
#include <algorithm>
#include <stdlib.h>
using namespace std;
int main () {
string s; cin >> s;
int x = 0;
for(int i=0; i<s.size(); i++) {
if(isdigit(s[i])) {
x += s[i]-'0';
}
}
cout << x << endl;
return 0;
}