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