/*
TASK:green
LANG:C++
*/
#include <stdio.h>
#define MAX 2000000000
int main()
{
   int N,M,i,j;
   double face, minface; int minv, minn;
   int x0,y0, x1,y1,x2,y2; 
   minface=(double)MAX;
   minv=MAX;
   minn=MAX;
   i=1;
   while(1)
   {
      scanf("%d",&M);
	  if(M==0) break;
	  face=0.;
      scanf("%d %d",&x1,&y1);
	  x0=x1;y0=y1;
	  for(j=2;j<=M;j++)
	  {
         scanf("%d %d",&x2,&y2);
		 face+=(x2-x1)*(y2+y1)/2;
		 x1=x2;y1=y2;
	  }
	  face+=(x0-x1)*(y0+y1)/2;
	  if(face<0) face= -face;
	  if((face<minface)||(face==minface&&M<minv))
	  {minface=face;minv=M;minn=i++;}

   }
   printf("%d\n",minn);
   return 0;
}