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

int main()
{
int i;
int iSum;
char S[ 20 ];
char C;

	cin >> S;

	iSum = 0;
	for( i = 0; i < 9; i++ )
	{
		C = S[ i ];
		if( C >= '1' && C <= '9' )
			iSum += (int) ( C - '0' );
		else
			iSum += 10;
	}

	cout << iSum << endl;

	return 0;
}