from decimal import Decimal, ROUND_DOWN



marume = 1

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

print(((Decimal(a) * Decimal(b)).quantize(Decimal(marume), rounding=ROUND_DOWN)))

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

a=int(a)

b=float(b)

print((int(a*int(100*b+0.5)//100)))
from decimal import Decimal, ROUND_DOWN

marume = 1
a, b = list(map(str, input().split()))
print(((Decimal(a) * Decimal(b)).quantize(Decimal(marume), rounding=ROUND_DOWN)))

a, b = list(map(str, input().split()))
a = int(a)
b = float(b)
print((int(a * int(100 * b + 0.5) // 100)))

-from decimal import Decimal, ROUND_DOWN - -marume = 1 -print(((Decimal(a) * Decimal(b)).quantize(Decimal(marume), rounding=ROUND_DOWN))) +a = int(a) +b = float(b) +print((int(a * int(100 * b + 0.5) // 100)))