#include <iostream>
#include <math.h>
#include <stdlib.h>
#include <cmath>
using namespace std;
 
int main()
{
    system(" COLOR FC");
    float circumference_of_circle_radius,radius ;
    cout << " Insert the radius of the circle:  \n";
    cin >> radius ;
    circumference_of_circle_radius = 2*(22/7)*radius;
    cout << fixed ;
    cout .precision(3);
    cout << "circumference_of_circle_radius = "<<circumference_of_circle_radius  << endl;
    return 0;
}
 

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