import Foundation

func mainC() {
    let AB = readLine()!.split(separator: " ")
    let nsA = NSDecimalNumber(string: String(AB[0]))
    let nsB = NSDecimalNumber(string: String(AB[1]))

    let result = nsA.multiplying(by: nsB).stringValue

    if let index = result.firstIndex(of: ".") {
        print(result.prefix(upTo: index))
    } else {
        print(result)
    }
}
mainC()