#include <bits/stdc++.h>
using namespace std;
const char en='\n';
int main(){
	cin.tie();
	ios::sync_with_stdio(false);
	string s;
	cin>>s;
	int sum=0;
	for(auto c:s){
		if('0'<=c&&c<='9')
			sum+=c-'0';
	}
	cout<<sum<<en;
	return 0;
}