#include <stdio.h>
#include <stdlib.h>

int n;    

#define min(a,b) ((a<b) ? a : b)
#define max(a,b) ((a>b) ? a : b)

typedef struct {
  int x;
  int y;
} TCoord;

TCoord poleX[100010];
TCoord poleY[100010];

int compareX(const void* arg1, const void* arg2) {
    TCoord b1 = *(TCoord*)(arg1);
    TCoord b2 = *(TCoord*)(arg1);
    if (b1.x<b2.x) return -1;
    if (b1.x>b2.x) return 1;
    if (b1.y<b2.y) return -1;
    if (b2.y>b2.y) return 1;
  return 0;
}

int compareY(const void* arg1, const void* arg2) {
    TCoord b1 = *(TCoord*)(arg1);
    TCoord b2 = *(TCoord*)(arg1);
    if (b1.y<b2.y) return -1;
    if (b2.y>b2.y) return 1;
    if (b1.x<b2.x) return -1;
    if (b1.x>b2.x) return 1;
  return 0;
}

int alg() {
    return 2*((poleX[n-1].x-poleX[0].x) + (poleY[n-1].y-poleY[0].y));
}

int main() {
    for (;;) {
        scanf("%d\n", &n);
	if (n==0) break;
	int x, y;
	int maxX = -1;
	int minX = 10001;
	int maxY = -1;
	int minY = 10001;
	for (int i=0; i<n; i++) {
	    scanf("%d%d", &x, &y);
//	    printf("%d %d\n", x, y);
	    minX=min(x, minX);
	    minY=min(y, minY);
	    maxX=max(x, maxX);
	    maxY=max(y, maxY);
	}
//	qsort(poleX, n, sizeof(TCoord), compareX);
//	qsort(poleY, n, sizeof(TCoord), compareY);
	printf("The length of the fence will be %d units.\n", 2*(maxX-minX+maxY-minY));
    }

    return 0;
}