hdu2098

/*Author :fisty *Data:2014-10-1 *hdu 2098 *水题啊。。 */#include <cstdio>#include <algorithm>using namespace std;#define MAX_N 10010int prime[MAX_N];void solve(){        for(int i = 0; i <= 10000; i++)                prime[i] = i;        for(int i = 2;i <= 100; i++){                if(prime[i] != 0){                        for(int j = i+i;j <= 10000; j += i)                                prime[j] = 0;                   }        }        }int main(){        int n;        solve();        while(scanf("%d", &n) != EOF){                if(!n) break;                int cnt = 0;                for(int i = 2;i < n/2 ; i++){                        if(prime[i] && prime[n-i]){                                        cnt++;                        }                }                printf("%d\n", cnt);        }        return 0;}