from decimal import *

a, b = input().split()

b = b.replace('.', '')



print((Decimal(a) * Decimal(b) // 100))
a, b = input().split()

b = b.replace('.', '')



print((int(a) * int(b) // 100))
from decimal import *

a, b = input().split()
b = b.replace(".", "")
print((Decimal(a) * Decimal(b) // 100))

a, b = input().split()
b = b.replace(".", "")
print((int(a) * int(b) // 100))

-from decimal import * - -print((Decimal(a) * Decimal(b) // 100)) +print((int(a) * int(b) // 100))