#include<stdio.h>
#include<math.h>
int main(){
    float radius, area;
    printf("Enter the radius of the circle:");
    scanf("%f", &radius);
    if(radius < 0){
        printf("Invalid Input\n");
    } else {
        area =  M_PI * radius * radius;
        printf("Area of the circle: %.2f\n", area);
    }
    return 0;
}