#include <stdio.h>

int parnih(unsigned n){
	if(n==0)
		return 0;
	if(n%2==0)
		return parnih(n/10)+1;
	else
		return parnih(n/10);
}

int main(){
	unsigned n;
	scanf("%u", &n);
	printf("Parnih cifara: %d\n", parnih(n));
	return 0;
}