import math

from decimal import *

A, B = list(map(str, input().split()))

print((math.floor(Decimal(A) * Decimal(B))))
import math

from decimal import Decimal

A, B = list(map(str, input().split()))

print((math.floor(Decimal(A) * Decimal(B))))
import math
from decimal import *

A, B = list(map(str, input().split()))
print((math.floor(Decimal(A) * Decimal(B))))

import math
from decimal import Decimal

A, B = list(map(str, input().split()))
print((math.floor(Decimal(A) * Decimal(B))))

-from decimal import * +from decimal import Decimal