#include <cstdio>
#include <iostream>
#include <algorithm>
#define rep(i,n) for(int i=0; i<n; i++)
#define REP(n) rep(i,n)
typedef long long ll;
using namespace std;


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