import math

a,b=input().split()

a=int(a)

c=int(b[0]+b[2]+b[3])

print((int(a*c)//100))

#print(a*b)
import math

a,b=input().split()

a=int(a)

c=int(b[0]+b[2]+b[3])

print((a*c//100))

#print(a*b)
import math

a, b = input().split()
a = int(a)
c = int(b[0] + b[2] + b[3])
print((int(a * c) // 100))
# print(a*b)

import math

a, b = input().split()
a = int(a)
c = int(b[0] + b[2] + b[3])
print((a * c // 100))
# print(a*b)

-print((int(a * c) // 100)) +print((a * c // 100))