poj 1552 [简单计算]

#include <iostream>
#include <cstdio>
#include <string>
#include <cstring>
#define BUG puts("here!!!")
using namespace std;
const int N = 105;
int a
;

int main() {
int i, num, count;
while(cin >> num, num != -1) {
memset(a, 0, sizeof(a));
count = 0;
a[num] = 1;
while(cin >> num, num) {
a[num] = 1;
}
for(i = 1; i < 50; i++) {
if(a[i] == 1 && a[2*i] == 1) {
count++;
}
}
printf("%d\n", count);
}
return 0;
}