#! /usr/bin/env python3



import sys

import math

import numpy as np

int1 = lambda x: int(x) - 1

read = sys.stdin.buffer.read

readline = sys.stdin.buffer.readline

readlines = sys.stdin.buffer.readlines

sys.setrecursionlimit(500000)



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



ans = int(A) * int(B * 1000000) // 1000000



print((int(ans)))
#! /usr/bin/env python3



import sys

import math

import numpy as np

int1 = lambda x: int(x) - 1

read = sys.stdin.buffer.read

readline = sys.stdin.buffer.readline

readlines = sys.stdin.buffer.readlines

sys.setrecursionlimit(500000)



A, B = readline().decode().rstrip().split()

A = int(A)

B = 100 * int(B[0]) + 10 * int(B[2]) + int(B[3])



ans = A * B // 100



print(ans)
#! /usr/bin/env python3
import sys
import math
import numpy as np

int1 = lambda x: int(x) - 1
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
sys.setrecursionlimit(500000)
A, B = list(map(float, readline().split()))
ans = int(A) * int(B * 1000000) // 1000000
print((int(ans)))

#! /usr/bin/env python3
import sys
import math
import numpy as np

int1 = lambda x: int(x) - 1
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
sys.setrecursionlimit(500000)
A, B = readline().decode().rstrip().split()
A = int(A)
B = 100 * int(B[0]) + 10 * int(B[2]) + int(B[3])
ans = A * B // 100
print(ans)

-A, B = list(map(float, readline().split())) -ans = int(A) * int(B * 1000000) // 1000000 -print((int(ans))) +A, B = readline().decode().rstrip().split() +A = int(A) +B = 100 * int(B[0]) + 10 * int(B[2]) + int(B[3]) +ans = A * B // 100 +print(ans)