#include <stdio.h>

int main(){
    float radius;

    printf("Please enter the radius : ");
    scanf("%f",&radius);

    if(radius < 0.0) printf("Cannot have a negative radius\n");
    else printf("The area of the circle is %f\n",3.1416 * pow(radius,2));

    int pause;
    scanf("%d",&pause);
    return 0;

}