import math

from decimal import *

a,b = input().split()

a = Decimal(a)

b = Decimal(b)

b = b*100

print((math.floor(a*b//100)))
import math

from decimal import *

a,b = input().split()

a = Decimal(a)

b = Decimal(b)

# b = b*100

print((math.floor(a*b)))
import math
from decimal import *

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

import math
from decimal import *

a, b = input().split()
a = Decimal(a)
b = Decimal(b)
# b = b*100
print((math.floor(a * b)))

-b = b * 100 -print((math.floor(a * b // 100))) +# b = b*100 +print((math.floor(a * b)))