import sys

readline = sys.stdin.readline



A,B = readline().split()

A = int(A)

B = int(float(B) * 100 + 0.5)



print((A * B // 100))
import sys

readline = sys.stdin.readline



A,B = readline().split()

A = int(A)

B = round(float(B) * 100)



print((A * B // 100))



import sys

readline = sys.stdin.readline
A, B = readline().split()
A = int(A)
B = int(float(B) * 100 + 0.5)
print((A * B // 100))

import sys

readline = sys.stdin.readline
A, B = readline().split()
A = int(A)
B = round(float(B) * 100)
print((A * B // 100))

-B = int(float(B) * 100 + 0.5) +B = round(float(B) * 100)