#include<stdio.h>
#include<stdlib.h>

typedef struct rectangle{
    float length;
    float width;
    struct rectangle *next;
}rect;

rect *head = NULL,*tail;



float area(float l,float w,float ar){
    ar = l*w;
    return ar;
}

int main(){
    float l,w,ar=0;
    
    scanf("%.2f",&l);
    scanf("%.2f",&w);
    if(l<0 || w<0){
        printf("Invalid input");
        return 0;
    }
    ar=area(l,w,ar);
    printf("%.2f",ar);
}