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

int main(){
	float xa,ya,xb,yb,xc,yc;
	float a,b,c,O,S,P;

	printf("Unesite koordinate xa,ya,xb,yb,xc,yc: ");
	scanf("%f %f %f %f %f %f",&xa,&ya,&xb,&yb,&xc,&yc);
		
	a = sqrt(powf(xb-xc,2)+powf(yb-yc,2));
	b = sqrt(powf(xa-xc,2)+powf(ya-yc,2));
	c = sqrt(powf(xa-xb,2)+powf(ya-yb,2));

	O = a+b+c;
	S = O/2;
	P = sqrt(S*(S-a)*(S-b)*(S-c));

	printf("O = %f, P = %f\n", O, P);
	return 0;
}