from decimal import Decimal

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

A=Decimal(a)

B=Decimal(b)



print((int(A*B)))



#b=int(B*100)

#ans100bai=A*b

#if len(str(ans100bai))>2:

#	print(str(ans100bai)[:-2])

#else:

#	print(0)



# 2darray [[0] * 4 for i in range(3)]

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

A=int(a)

B=int(b.replace(".",""))



print((A*B//100))

from decimal import Decimal

a, b = list(map(str, input().split()))
A = Decimal(a)
B = Decimal(b)
print((int(A * B)))
# b=int(B*100)
# ans100bai=A*b
# if len(str(ans100bai))>2:
# 	print(str(ans100bai)[:-2])
# else:
# 	print(0)
# 2darray [[0] * 4 for i in range(3)]

a, b = list(map(str, input().split()))
A = int(a)
B = int(b.replace(".", ""))
print((A * B // 100))

-from decimal import Decimal - -A = Decimal(a) -B = Decimal(b) -print((int(A * B))) -# b=int(B*100) -# ans100bai=A*b -# if len(str(ans100bai))>2: -# 	print(str(ans100bai)[:-2]) -# else: -# 	print(0) -# 2darray [[0] * 4 for i in range(3)] +A = int(a) +B = int(b.replace(".", "")) +print((A * B // 100))