HDU 1303 Doubles

#include 
#include 
#include 
using namespace std;
int main()
{
	int i,j,k,a[233]={0};
	while(cin>>i){
		if(i==-1) break;
		a[i]++;
		if(i==0){
			
			k=0;
			for(j=2;j<=100;j+=2){
			   if(a[j/2]>0) k+=a[j]; 
			 } 
			 cout<