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

int main(){
	long a;
	double b;
	long mult;
	
	if(scanf("%lu %lf",&a,&b) != 2){
		perror("scanf");
		exit(1);
	}
	mult = (long)(a*b);
	printf("%lu",mult);
	return 0;
}