/*
TASK:GREEN
LANG:C
*/

#include<stdio.h>
#include<math.h>

double smin = 2000000000;

int main()
{
        int i, x1, y1, j, x2, y2, x3, y3;
        int m, im = 0, brvm = 101, brvt = 0;
        double s = 0;
        for(j = 1;; j++){
                s = 0;
                scanf("%d", &m);
                if(m == 0) break;
                scanf("%d", &x1);
                scanf("%d", &y1);
                scanf("%d", &x2);
                scanf("%d", &y2);
                scanf("%d", &x3);
                scanf("%d", &y3);
                s = s + abs((x1-x2)*(y2-y3)-(x2-x3)*(y1-y2))/2;
                for(i = 3; i <  m; i++)
                {
                    x2 = x3;
                    y2 = y3;
                    scanf("%d", &x3);
                    scanf("%d", &y3);
                    s = s + abs((x1-x2)*(y3-y2)-(x3-x2)*(y1-y2))/2;
                }
                if(s < smin)
                {
                        smin = s;
                        im = j;
                }
                if(s == smin && m < brvm)
                {
                        smin = s;
                        im = j;
                        brvm = m;
                }
        }

        printf("%d\n", im);

        return 0;
}






