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

#define max 1000000000000000000
#define Amax 100000

int main()
{

	long long int A=0;
	double B=0;

	scanf("%lld %lf",&A,&B);


	printf("%lld",(long long int)(A*B));

	return 0;
}
