import sys

import math



sys.setrecursionlimit(10 ** 9)

input = sys.stdin.readline



A, B = list(map(float, input().split()))

A = int(A)

B_tmp = int(B * 10**2 + 0.5)



total = A * B_tmp

total //= 100

# total = math.floor(total)

print((int(total)))

import sys



sys.setrecursionlimit(10 ** 9)

input = sys.stdin.readline



A, B = list(map(float, input().split()))

A = int(A)

B = int(B * 10**2 + 0.5)



total = A * B

total //= 100

print(total)

import sys
import math

sys.setrecursionlimit(10**9)
input = sys.stdin.readline
A, B = list(map(float, input().split()))
A = int(A)
B_tmp = int(B * 10**2 + 0.5)
total = A * B_tmp
total //= 100
# total = math.floor(total)
print((int(total)))

import sys

sys.setrecursionlimit(10**9)
input = sys.stdin.readline
A, B = list(map(float, input().split()))
A = int(A)
B = int(B * 10**2 + 0.5)
total = A * B
total //= 100
print(total)

-import math -B_tmp = int(B * 10**2 + 0.5) -total = A * B_tmp +B = int(B * 10**2 + 0.5) +total = A * B -# total = math.floor(total) -print((int(total))) +print(total)