#include <iostream>
#include <string>
using namespace std;
#define rep(i,n) for(int i=0;i<(n);i++)

int main(void){
	string s; cin >> s;
	int ans = 0;
	rep(i, s.size()){
		if('0' <= s[i] && s[i] <= '9'){
			ans += s[i] - '0';
		}
	}
	cout << ans << endl;
	return 0;
}