#include <iostream>
#include <string>
using namespace std;

int main(void){
//input
	string str;
	cin >> str;
//calc
	int sum=0;
	
	for(int i=0;i<str.size();i++){
		if(str[i] >= '0' && str[i] <= '9'){
			sum += str[i] - '0';
		}
	}
//output
	cout << sum ;
}