HDU 素数判定

#include<stdio.h>
int x,y,f,n;
int judge( int x  )
{
    for( int i = 2; i <= x / 2;++i )
         if( x % i == 0 )
         {
             return 0;
         }
    return 1;
}
int main( )
{
    while( scanf( "%d%d",&x,&y ),x|y )
    {
           f = 1;
           for( ;x <= y; ++x )
                if( !judge( x*x+x+41 ) )
                {
                    f = 0;
                    break;
                }
           puts( f ?"OK":"Sorry" );
           }
    return 0;
}