/*
 * FileName:     C
 * CreatedDate:  2020-05-31 20:58:51 +0900
 * LastModified: 2020-05-31 21:55:06 +0900
 */

#include <stdio.h>

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