#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MOD 1000000007
#define INF 1000000000000000000
#define PI 3.14159265359
#define ull unsigned long long
#define MYPOW_t int

int main(){
    long long a;
    long double b;
    scanf("%lld%f",&a,&b);
    
    printf("%lld",(long long)a*b);
    return 0;
}


