#include <stdio.h>
#include <math.h>

int main()
{
    int r, h;
    scanf("%d", &r);
    scanf("%d", &h);

    if (r < 0 || h < 0)
    {
        printf("Invalid input\n");
        return 0;
    }

    double surface_area = 2 * M_PI * r * (r + h);
    printf("%.2f\n", surface_area);

    return 0;
}