/*
TASK:green
LANG:C
*/
#include<stdio.h>
double b[1000000]={0};
int main(){
int n;
long i,j,k,l;
double s=0;
double e,f,h;
int a[404]={0};
//freopen("green.in","rt",stdin);
//freopen("green.out","wt",stdout);
j=0;
while(1)
    {
    scanf("%d",&n);
    if  (!n) break;
    for (i=0;i<2*n;i++)
        scanf("%d",&a[i]);
    a[2*n]=a[0];
    a[2*n+1]=a[1];
    for (i=2*n+2;i<4*n+3;i+=2)
        {
        a[i]=a[i-(2*n+2)];
        a[i+1]=0;
        }    
     /*for (i=0;i<4*n+4;i++) printf("%d ",a[i]);
     printf("\n");
     */
     //namirane na e,f,h formula (e+f)*h/2
     for (i=0;i<2*n;i+=2)
         {
         e=sqrt((a[i]-a[i+ 2*n+2])*(a[i]-a[i+ 2*n+2])+(a[i+1]-a[i+ 2*n+2+1])*(a[i+1]-a[i+ 2*n+2+1]));
         f=sqrt((a[i+2]-a[i+ 2*n+2+2])*(a[i+2]-a[i+ 2*n+2+2])+(a[i+1+2]-a[i+ 2*n+2+1+2])*(a[i+1+2]-a[i+ 2*n+2+1+2])); 
         h=sqrt((a[i+2*n+2]-a[i+2*n+4])*(a[i+2*n+2]-a[i+2*n+4])+(a[i+2*n+3]-a[i+2*n+5])*(a[i+2*n+2+3]-a[i+2*n+5]));
         s=((e+f))*h/2;
	 //if  ((abs(a[i])-abs(a[i+2]))<0) b[j]+=s;
	 if  ((a[i]-abs(a[i+2]))<=0) b[j]+=s;
	 else b[j]-=s;
	 }
	 j++;
     }
//printf("%lf",b[0]);
s=b[0];
k=0;
for (i=1;i<j;i++)
    if  (s>b[i]) {s=b[i];k=i;}
printf("%ld\n",k+1);
//printf("%lf %d %d",b[k],k,k+1);    
//for (i=0;i<j;i++) printf("%lf ",b[i]);
return 0;
}
        
