#include<iostream>
using namespace std;

double cons(double R1,  double R2) {
	return(R1 + R2);
}

double par(double R1,  double R2) {
	return ((R1*R2) / (R1 + R2));
}


void main(void) {
	cout << "Type down 4 circuit elememts \n";
	double R1, R2, R3, R4;
	cin >> R1 >> R2 >> R3 >> R4;

	cout << "Resistance on 1st ciruit = ";
	cout << cons( cons (cons(R1, R2),R3),R4) << endl;
	cout << "Resistance on 2nd ciruit = ";
	cout << cons(par(R2, R4), R1) << endl;
	cout << "Resistance on 3d ciruit = ";
	cout << cons(cons(R3, par(cons(R2, par(R1,R3)), cons(R1,R4))),R4) << endl;

	_getwch();

}