import math

from decimal import *

getcontext().prec = 28

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

a_ = Decimal(a)

b_ = Decimal(b)

#b = b*100

#print(round(Decimal(Decimal(a)*Decimal(b))))

print((math.floor(a_*b_)))

#print(math.floor(Decimal(a)*Decimal(b)/Decimal(100.0)))
s,t =input().split()

a = int(s)

b = int(float(t)*1000)

ans = a*b

print((ans//1000))

import math
from decimal import *

getcontext().prec = 28
a, b = list(map(str, input().split()))
a_ = Decimal(a)
b_ = Decimal(b)
# b = b*100
# print(round(Decimal(Decimal(a)*Decimal(b))))
print((math.floor(a_ * b_)))
# print(math.floor(Decimal(a)*Decimal(b)/Decimal(100.0)))

s, t = input().split()
a = int(s)
b = int(float(t) * 1000)
ans = a * b
print((ans // 1000))

-import math -from decimal import * - -getcontext().prec = 28 -a, b = list(map(str, input().split())) -a_ = Decimal(a) -b_ = Decimal(b) -# b = b*100 -# print(round(Decimal(Decimal(a)*Decimal(b)))) -print((math.floor(a_ * b_))) -# print(math.floor(Decimal(a)*Decimal(b)/Decimal(100.0))) +s, t = input().split() +a = int(s) +b = int(float(t) * 1000) +ans = a * b +print((ans // 1000))