#include <stdio.h>
#include <conio.h>
#include <iostream.h>

main()
{
      float keliling,phi;
      int r;
      const float PI = 3.14;
      cout<<"masukan jari-jari lingkaran=";
      cin>>r;
      keliling=2*PI*r;
      cout<<"keliling lingkaran ="<<keliling;
      getch();
      }