from decimal import *

def main():

    a, b = list(map(str, input().split()))

    res = int(a) * Decimal(b)

    print((int(res)))



if __name__ == '__main__':

    main()
def main():

  

    a, b = list(map(str, input().split()))

    res = int(a) * round((float(b)) * 100) // 100

    print(res)

 

if __name__ == '__main__':

    main()
from decimal import *


def main():
    a, b = list(map(str, input().split()))
    res = int(a) * Decimal(b)
    print((int(res)))


if __name__ == "__main__":
    main()

def main():
    a, b = list(map(str, input().split()))
    res = int(a) * round((float(b)) * 100) // 100
    print(res)


if __name__ == "__main__":
    main()

-from decimal import * - - -    res = int(a) * Decimal(b) -    print((int(res))) +    res = int(a) * round((float(b)) * 100) // 100 +    print(res)