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

typedef struct Tacka{
	double x,y;
} tacka;

double rastojanje(tacka t1, tacka t2){
	return sqrt((t1.x-t2.x)*(t1.x-t2.x)+(t1.y-t2.y)*(t1.y-t2.y));
}

double obim(tacka *t, int n){
	double o = 0;
	int i;
	for(i=0; i<n-1; i++)
		o+=rastojanje(t[i],t[i+1]);
	o+=rastojanje(t[0],t[n-1]);
	return o;
}

double heron(tacka t1, tacka t2, tacka t3){
	double s,a,b,c;
	a = rastojanje(t1,t2);
	b = rastojanje(t2,t3);
	c = rastojanje(t3,t1);
	s = (a+b+c)/2;
	return sqrt(s*(s-a)*(s-b)*(s-c));
}

double povrsina(tacka *t, int n){
	int i;
	double p=0;
	for(i=1; i<n-1; i++)
		p+=heron(t[0],t[i],t[i+1]);
	return p;
}

int main(){
	int n;
	int i;
	tacka *t;
	
	scanf("%d",&n);
	
	t=(tacka*)malloc(n*sizeof(tacka));

	for(i=0; i<n; i++){
		scanf("%lf %lf",&(t[i].x), &(t[i].y));
	}

	for(i=0; i<n; i++)
		printf("%lf %lf\n",t[i].x,t[i].y);

	printf("Obim je: %lf\nPovrsina je: %lf\n", obim(t,n),povrsina(t,n));

	return 0;
}