import java.util.*
import java.math.*
import java.lang.Math.*

val readString: ()->String = {readLine()!!}
val readInt: ()->Int = {readLine()!!.toInt()}
val readLong: ()->Long = {readLine()!!.toLong()}
val readIntArray: ()->IntArray = {readLine()!!.split(' ').map{it.toInt()}.toIntArray()}
val readLongArray: ()->LongArray = {readLine()!!.split(' ').map{it.toLong()}.toLongArray()}
val errPrintln: (String)->Unit = {msg -> System.err.println(msg)}
val MOD = 1e9.toLong()+7
val INF = Int.MAX_VALUE/2
val LINF = Long.MAX_VALUE/2


fun main(args: Array<String>) {
    val (SA, SB) = readString().split(' ')
    val A = SA.toBigDecimal()  // [0, 1e15]
    //val B = SB.toDouble()  // [0.00, 9.99]
    val B = SB.toBigDecimal()

    if (A==0.toBigDecimal() || B==0.toBigDecimal()) {
        println(0)
        return
    }

    val ans = A * B

    println(ans.toLong())
}
