hdu 2095 异或“找不同”

#include <cstdio>
using namespace std;

int main ()
{
int n;
while ( scanf("%d", &n), n )
{
int ans = 0, tmp;
for ( int i = 0; i < n; i++ )
{
scanf("%d", &tmp);
ans = ans ^ tmp;
}
printf("%d\n", ans);
}
return 0;
}