#include<studio.h>
struct rectangle {
    float length;
    float width;
    
};
void calculateArea(struct rectangle rect) {
    if(rect.length<0 || rect.width< 0) {
        print("Invalid input\n");
    }
    else {
        float area=rect.length*rect.width;
        print("%.2f\n",area);
    }
}
int main() {
    struct rectangle plot;
    scanf("%f", &plot.length);
    scanf("%f", &plot.width);
    calculateArea(plot);
    return 0;
}