#include <iostream>
#include <string>
using namespace std;
int main(){
	string s;	cin>>s;
	int cnt=0;
	for(int i=0;i<(int)s.size();i++){
		if('0'<=s[i]&&s[i]<='9')	cnt+=s[i]-'0';
	}
	cout<<cnt<<endl;
	return 0;
}