#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
typedef long long int ll;

int main(){
	cin.tie(nullptr);
	ios::sync_with_stdio(false);
	string s; cin >> s;
	int sum=0;
	for(char c:s){
		if('0'<=c&&c<='9'){
			sum+=(c-'0');
		}
	}
	cout << sum << endl;
}