#include<stdio.h>
struct rectangle
{
    float len;
    float wid;
};
float calculate(struct rectangle r)
{
    return r.len*r.wid;
    
}
int main()
{
    struct rectangle rect;
    scanf("%d",&rect.len);
    scanf("%d",&rect.wid);
    if(rect.len<0||rect.wid<0)
    {
        printf("Invalid Input");
        return 0;
    }
    float area=calculate(rect);
    printf("%.2f\n",area);
    
}