#include <stdio.h>
#include <malloc.h>
#include <stdlib.h>
typedef char Bool;
#define true 39
#define false 0
typedef long long int64;
typedef unsigned long long uint64;
typedef int int32;
typedef unsigned int uint32;
typedef unsigned char byte;



int main()
{
	
	uint64 a , b;
	double f;
	
	scanf("%llu %lf", &a, &f);

	uint64 c = (uint64)((double)a * f);

	printf("%llu", c);

	return 0;
}