#include<iostream>
#include<stdio.h>
#include<algorithm>
#include<vector>
#include<string.h>
#include<math.h>
#include<map>
#include<iomanip>
#include<queue>

const long long INF = 1e6+7;
const long long MOD = 1e9+7;
const double PI=acos(-1);

using namespace std;

int main(){
	string s;
	cin >> s;
	int sum=0;
	for(int i=0;i<s.size();i++){
		if('1' <= s[i] && s[i] <= '9'){
			sum+=(int)(s[i]-'0');
		}
	}
	cout << sum << endl;
	return 0;
}