#include <stdio.h>

int main (){
	int n,digit,sum=0;
	scanf("%d",&n);
	while(n!=0)
	{
		digit =n%10;
		if(digit%2==0)
		{
			sum=sum +digit;
		}
		n=n/10;
	}
	printf("sum of even digits=%d\n",sum);

return 0;
}