#include <bits/stdc++.h>
using namespace std;

int main()
{
int i;
int iSum;
char S[ 10100 ];
char C;

	cin >> S;

	i = 0;
	iSum = 0;
	while( C = S[ i ] )
	{
		if( C >= '1' && C <= '9' )
			iSum += ( C - '0' );

		i++;
	}

	cout << iSum << endl;

	return 0;
}