#include<stdio.h>
struct Rectangle{
    float length;
    float width;
};
float CalculateArea(struct Rectangle r){
    return r.length*r.width;
}
int main(){
    struct Rectangle rt;
    scanf("%f %f",&rt.length,&rt.width);
    if(rt.length<0 ||rt.width<0){
        print("Invalid Input");
        return 0;
    }
    else{
        float area=CalculateArea(rt);
        printf("%.2f",area);
    }
    return 0;
}