A,B = input().split()

A = int(A)

B = int(float(B)*100+1.0e-10)

print((int((A*B)//100)))



# C - Multiplication 3

A,B = input().split()

A = int(A)

B = int(100*float(B)+0.001)

print(((A*B)//100))
A, B = input().split()
A = int(A)
B = int(float(B) * 100 + 1.0e-10)
print((int((A * B) // 100)))

# C - Multiplication 3
A, B = input().split()
A = int(A)
B = int(100 * float(B) + 0.001)
print(((A * B) // 100))

+# C - Multiplication 3 -B = int(float(B) * 100 + 1.0e-10) -print((int((A * B) // 100))) +B = int(100 * float(B) + 0.001) +print(((A * B) // 100))