#include <cstdio>

using namespace std;

double x1,y1,x2,y2,x3,y3,x4,y4,dx1,dy1,dx2,dy2;

signed main()
{
   while( scanf("%lf %lf %lf %lf %lf %lf %lf %lf", &x1, &y1, &x2, &y2, &x3, &y3, &x4, &y4 ) != EOF )
   {
       dx1 = x2 - x1, dy1 = y2 - y1;
       dx2 = x4 - x3, dy2 = y4 - y3;
       double in = dx1 * dx2 + dy1 * dy2;
       
       if( in < 0.0000001 )
       {
           printf( "YES\n" );
       }
       else
       {
           printf( "NO\n" );
       }
   }
   return 0;
}
