peterverebics/CodeNet_Python_118 huggingface dataset:
import math
n = int(input())

for i in range(1,50000):
    if int(i*1.08) == n:
        print(i)
        exit()
    elif int(i*1.08) > n:
        print(':(')
        exit()
n = int(input())

for x in range(1,n+1):
    if n==int(x*1.08):
        print(x)
        exit()
print(":(")
N = int(input(""))
ans = int(N/1.08)-1
f = 0
while ans < (N/1.08)+1:
    if int(ans*1.08) == N:
        print(ans)
        f += 1
    ans += 1
if f == 0:
    print(":(")
taxed_price = int(input())
raw_price = taxed_price // 1.08

if int(raw_price * 1.08) == taxed_price:
    print(int(raw_price))
elif int((raw_price + 1) * 1.08) == taxed_price:
    print(int(raw_price + 1))
else:
    print(':(')
def main():
    n = int(input())

    for i in range(1, 50000):
        if i * 108 // 100 == n:
            print(i)
            break
    else:
        print(":(")


if __name__ == "__main__":
    main()
n = int(input())

f = False
for i in range(n+1):
    if int(i*1.08)==n:
        print(i)
        f = True
        break
if not f:
    print(':(')
import math

n = int(input())

for i in range(1, 50001):
    x = math.floor(i * 1.08)
    if x == n:
        print(i)
        break
else:
    print(":(")
n = int(input())

for x in range(1, 10**5):
	if int(x * 1.08) == n:
		print(x)
		exit()
print(':(')
n = int(input())

base = n // 1.08
cands = [base-1, base, base+1]
flag = False
for cand in cands:
    if cand * 1.08 >= n and n > cand * 1.08 - 1:
        print(int(cand))
        flag = True
        break

if not flag:
    print(':(')
n = int(input())

n_origin = int(n * 100 / 108.)

if int(n_origin * 108 / 100) == n:
  print(n_origin)
elif int((n_origin+1) * 108 / 100) == n:
  print(n_origin+1)
else:
  print(":(")
from math import ceil


def main():
    n = int(input())

    min_value = n * 100 / 108
    max_value = (n + 1) * 100 / 108

    candidate = ceil(min_value)

    if candidate < max_value:
        print(candidate)
    else:
        print(":(")


if __name__ == "__main__":
    main()
def resolve():
    x = int(input().strip())
    a =int( x // 1.08 )
    b =int( -1 * (-1 * x // 1.08))
    ans = ':('
    if int(a * 1.08) == x:
        ans = int(a)
    if int(b * 1.08) == x:
        ans = int(b)
    print(ans)
resolve()
import math
n=int(input())
x0 = n * 100 / 108
x1 = (n+1) * 100 / 108

if x0.is_integer():
    print(math.floor(x0))
elif x1.is_integer():
    print(':(')
elif math.floor(x0) != math.floor(x1):
    print(math.floor(x1))
else:
    print(':(')
import math
n = float(input())
m_low = math.ceil(n / 1.08)
m_high = math.floor((n+1)/1.08)
if m_low > m_high:
  print(':(')
else:
  ch_low = math.floor(m_low*1.08)
  ch_high = math.floor(m_high*1.08)
  if ch_low == int(n):
    print(m_low)
  elif ch_high == int(n):
    print(m_high)
  else:
    print(':(')
# coding: utf-8

N = int(input())

x_ = N//1.08
ans = ':('
for i in range(1,100000):
    x = x_+i
    if int(1.08*x) == N:
        ans = int(x)
        break

print(ans)
from math import ceil, floor

n = int(input())
res = ceil(n/1.08)
if floor(res*1.08) == n:
    print(res)
else:
    print(":(")
N = int(input())

for i in range(50000):
    if N == i*108//100:
        print(i)
        break
else:
    print(":(")
def main():
    n = int(input())
    p = n * 25 // 27
    a, b = int(p * 1.08), int((p + 1) * 1.08)
    if a == n:
        print(p)
    elif b == n:
        print(p + 1)
    else:
        print(":(")

if __name__ == "__main__":
    main()
import math
N=int(input())
#print(N*100/108)
if N * 100 % 108 == 0:
    print(N*100//108)
else:
    kouho=N * 100 // 108
    for i in range(-1,2):
        #print(math.floor((kouho + i) * 1.08))
        if N == math.floor((kouho + i) * 1.08):
            print(kouho + i)
            exit()
    print(":(")
n = int(input())
x = n/1.08
if x != int(x):
  x = int(x) + 1
else:
  x = int(x)
if n == int(x*1.08):
  print(x)
else:
  print(":(")
import math
n = int(input())
flag = False

for i in range(1,n+1000):
    if math.floor(i*1.08) == n:
        flag = True
        ans = i
        break

if flag:
    print(ans)
else:
    print(":(")
import math
n=int(input())
x=math.ceil(n*100/108)
if n==math.floor(x*1.08):
	print(x)
else:
	print(':(')
n = int(input())

for i in range(1,n+1):
  txd = int(i*1.08)
  if n==txd:
    print(i)
    exit()
print(":(")
#B(別解)
import math
n=int(input())
x=math.ceil(n/1.08)
if math.floor(x*1.08)==n:
    print(x)
else:
    print(":(")
import math
N = int(input())
downer = math.ceil(N/1.08)
upper = math.floor((N+1)/1.08-0.0000000001)
A = [i for i in range(downer,upper+1)]
for i in range(len(A)):
    if math.floor(A[i]*1.08) == N:
      print(A[i])
      exit()
print(':(')
# coding: utf-8

def main():
    N = int(input())
    ans = ':('

    for i in range(50001):
        if int(i * 1.08) == N:
            ans = i
            break

    print(ans)


if __name__ == "__main__":
    main()
from math import ceil,floor

N=int(input())
X=ceil(N/1.08)
print(X if floor(X*1.08)==N else ":(")
import math

N = int(input())

ans = math.ceil(N/1.08)

if math.floor(ans * 1.08) != N:
    print(':(')
else:
    print(ans)
# print(math.ceil(N/1.08))
# print(int(math.ceil(N/1.08)*1.08))
n = int(input())
stp = int(n/1.08)
while True:
  cost = int(stp*1.08)
  if cost == n:
    ans = stp
    break
  elif cost > n:
    ans = ':('
    break
  else:
    stp += 1
print(ans)
import math

n = int(input())

x = (n/1.08)

a = x//1
b = math.ceil(x)

if a*1.08//1 == n :
    print(math.ceil(a))
elif b*1.08//1 == n :
    print(b)
else:
    print(":(")
import math
n = int(input())
x = math.ceil(n / 1.08)
print(':(' if int(x * 1.08) != n else x)
"""Boot-camp-for-Beginners_Easy004_B_Tax-Rate_25-August-2020.py"""
import numpy as np
import sys

N=int(input())
X=N/1.08
if int(int(np.ceil(X))*1.08)==N:
    print(int(np.ceil(X)))
else:
    print(":(")
N = int(input())

from math import floor

ans = 0
for x in range(1,50001):
    if N == floor(x*1.08):
        ans = x

if ans == 0:
    print(':(')
else:
    print(ans)
import math
N =  int(input())

a = N/1.08
b = (N+1)/1.08

if b-math.ceil(a) <= 0:
    print(':(')
else:
    print(math.ceil(a))
n = int(input())

if n/1.08==n//1.08:
    print(n//1.08)
elif int(-(-n//1.08) * 1.08) == n:
    print(int(-(-n//1.08)))
else:
    print(':(')
import math
a = input()
N = int(a)

X = N//1.08 + 1
x = math.floor(X*1.08)
if x == N:
    print(int(X))
else:
    print(':(')
n = int(input())

if (n + 1) % 108 == 0:
    print(':(')
else:
    if n % 108 == 0:
        print(n // 108 * 100)
    else:
        a = int(n / 1.08)
        for i in range(a, a + 3):
            s = i * 1.08
            if n <= s and s < n + 1:
                print(i)
                break
            if i == a + 2:
                print(':(')
from sys import stdin

n = int(stdin.readline().strip())
x1 = n // 1.08
x2 = n // 1.08 + 1

if int(x1 * 1.08) == n:
  print(int(x1))
elif int(x2 * 1.08) == n:
  print(int(x2))
else:
  print(":(")
n = int(input())
for x in range(n + 1):
    if x * 108 // 100 == n:
        print(x)
        break
else:
    print(':(')
import math
n = int(input())
div = math.ceil(n/1.08)

if math.floor(div*1.08)==n:
    print(div)
else:
    print(':(')
import sys


inint = lambda: int(sys.stdin.readline())
inintm = lambda: map(int, sys.stdin.readline().split())
inintl = lambda: list(inintm())
instrm = lambda: map(str, sys.stdin.readline().split())
instrl = lambda: list(instrm())

n = inint()

if int(-(-n//1.08) * 1.08) != n:
    print(":(")
else:
    print(int(-(-n//1.08)))
N = int(input())
 
for i in range(1, N + 1):
  if i + (i * 8) // 100 == N:
    print(i)
    break
else:
  print(":(")
#!/usr/bin/env python3
x = int(input())
for i in range(50000):
    if int(i * 1.08) == x:
        print(i)
        quit()
print(':(')
# B - Tax Rate

N = int(input())

for i in range(1, 50001):
    if int(i * 1.08) == N:
        print(i)
        break
else:
    print(':(')
n = int(input())

for i in range(1,50001):
    if (i*1.08)//1 == n:
        print(i)
        exit()
    if (i*1.08)//1 > n:
        print(':(')
        exit()
n=int(input())
for x in range(60000):
  if int(x*1.08)==n:
    print(x)
    exit()
print(":(")
import sys
import math
def S(): return sys.stdin.readline().rstrip()
def I(): return int(sys.stdin.readline().rstrip())
def LI(): return list(map(int,sys.stdin.readline().rstrip().split()))
def LS(): return list(sys.stdin.readline().rstrip().split())

N = I()

x = math.ceil(N / 1.08)
if math.floor(x * 1.08) == N:
    print(x)
else:
    print(":(")
import math
N = int(input())

for i in range(N+1):
  if math.floor(i*1.08) == N:
    print(i)
    exit()
print(':(')
# -*- coding: utf-8 -*-

# N円の支払い (1 ≤ N ≤ 50000)
N = int(input())#入力

count = 0
for x in range(50000):
    if(N == int(x*1.08)):
        without_tax = x #税抜き価格
    else: count = count + 1

if(count == 50000): print(':(')
else: print(without_tax)
import math
n = int(input())
a = math.floor(n/1.08)
if a*1.08 >= n:
    print(a)
elif (a+1)*1.08 >= n and (a+1)*1.08 < n+1:
    print(a+1)
else:
    print(':(')
n = int(input())
for i in range(50001):
  if int(i * 1.08) == n:
    print(i)
    exit()
print(":(")
n=int(input())
ans=0
for i in range(1,50000+1):
    z=i*1.08
    if n<=z<(n+1):
        ans=i
        break
if ans==0:
    print(":(")
else:
    print(ans)
N = int(input())
for i in range(1,50001):
  if i*108//100 == N:
    print(i)
    exit()
print(':(')
N = int(input())
X = int(-(-N // 1.08))
print(X if int(X * 1.08) == N else ':(')
import math

n = int(input())

ans = math.ceil(n/1.08)

if n == int(ans*1.08):
  print(ans)
else:
  print(":(")
import math

N = int(input())
A = N // 1.08
A2 = A + 1

if math.floor(A * 1.08) == N:
	ans = int(A)
	print(ans)
elif math.floor(A2 * 1.08) == N:
	ans = int(A2)
	print(ans)
else:
	print(":(")
import math

N = int(input())

X = math.ceil(N / 1.08)

if math.floor(X * 1.08) == N:
    print(X)
else:
    print(':(')
n = int(input())
ans = int(n/1.08)

for i in range(2):
    if int(ans*1.08) == n:
        print(ans)
        exit()
    ans += 1

print(":(")
import math

N = int(input())

lower = N / 1.08

vl = math.ceil(lower)

if math.floor(vl * 1.08) == N:
  print(vl)
else:
  print(":(")
import math
import sys
readline = sys.stdin.readline


def main():
    n = int(readline().rstrip())

    for i in range(50001):
        k = math.floor(i * 1.08)
        if n == k:
            print(i)
            return
    print(':(')


if __name__ == '__main__':
    main()
N = int(input())
ans=-1

for i in range(1,N+1):
       if int( i*1.08) == N:
            ans = i
            
if ans == -1:
    print(':(')
else:
    print(ans)
from math import floor, ceil
n = int(input())
f = floor(n/1.08)
c = ceil(n/1.08)
n2 = floor(f*1.08)
n3 = floor(c*1.08)
if n == n2:
    print(f)
elif n == n3:
    print(c)
else:
    print(':(')
import math
n = int(input())
temp_p = math.ceil(n / 1.08)
if math.floor(temp_p * 1.08) == n:
    print(temp_p)
else:
    print(":(")
import math
N = int(input())

for i in range(N+1):
    if math.floor(1.08 * i) == N:
        print(i)
        exit()

print(":(")
import math

N = int(input())
x = int(math.ceil(N / 1.08))

if int(x * 1.08) == N:
    print(x)
else:
    print(":(")
import sys
import math
def S(): return sys.stdin.readline().rstrip()
def I(): return int(sys.stdin.readline().rstrip())
def LI(): return list(map(int,sys.stdin.readline().rstrip().split()))
def LS(): return list(sys.stdin.readline().rstrip().split())

N = I()
flag = 0
for i in range(1,N+1):
    if math.floor(i*1.08) == N:
        print(i)
        flag = 1
        break

if flag == 0:
    print(":(")
N = int(input())
 
ans = ":("
 
for X in range(N+1):
  if int(X * 1.08) == N:
    ans = X
    break
    
print(ans)
n=int(input())

t=n/1.08

f=0
if int(t)*1.08 >= n:
  f=int(t)
else:
  f=int(t)+1

if int(f*1.08) == n:
  print(f)
else:
  print(":(")
N = int(input())
for x in range(1, 50000):
    if int(x * 1.08) == N:
        print(x)
        exit()
print(":(")
N = int(input())


for i in range(N+1):
    X = i * 1.08
    if int(X) == N:
        print(i)
        exit()

print(':(')
N = int(input())
div = int(N / 1.08)
if int(int(div) * 1.08) == N:
    print(div)
elif int(int(div + 1) * 1.08) == N:
    print(div + 1)
else:
    print(":(")
n = int(input())

for i in range(500000):
  if int(i*1.08) == n:
    print(i)
    break
else:
  print(":(")
import math
n = int(input())

x = n /1.08
price= math.ceil(x)

if math.floor(price*1.08) == n:
    print(price)
else:
    print(':(')
#-*-coding:utf-8-*-
import sys
input=sys.stdin.readline

import decimal

def main():
    tax = decimal.Decimal('1.08')
    n = int(input())

    for i in range(1,n+1):
        if int(i*tax)==n:
            print(i)
            exit()
        else:
            continue
    print(":(")

if __name__=="__main__":
    main()
import math

n = int(input())
ans = math.ceil(n/1.08) 
if n != math.floor(ans*1.08):
    print(r':(')
else:
    print(ans)
n=int(input())

for x in range(55000):
    if int(x*1.08)==n:
        print(x)
        exit()
print(":(")
N = int(input())
N_o = int(N/1.08)
if int(N_o * 1.08) == N:
    print(N_o)
else:
    if int((N_o+1)*1.08) == N:
        print(N_o+1)
    elif  int((N_o-1)*1.08) == N:
        print(N_o-1)
    else:
        print(':(')
n = int(input())
a = {int(i*1.08):i for i in range(1, 5*10**4+1)}
if n in a:
    print(a[n])
else:
    print(':(')
N = int(input())
for x in range(1, 5 * 10000 + 1):
    if int(x * 1.08) == N:
        print(x)
        break
else:
    print(":(")
import math
N = int(input())

X = math.ceil(N / 1.08)

if (math.floor(X * 1.08) == N):
    print(X)
    exit()
print(':(')
N = int(input())
for i in range(int(N * 0.9), N + 1):
    if int(i * 1.08) == N:
        print(i)
        break
else:
    print(':(')
import sys
input = sys.stdin.readline
sys.setrecursionlimit(10 ** 7)

n = int(input())

def bs(ok, ng, cond):
    while abs(ok - ng) > 1:
        mid = (ok + ng) // 2
        if cond(mid):
            ok = mid
        else:
            ng = mid
    return ok

ans = bs(n, 0, lambda x: x * 1.08 >= n)
if n == int(ans * 1.08):
    print(ans)
else:
    print(':(')
n=int(input())
for i in range(50000):
    if int(i*1.08)==n:
        print(i)
        exit()
    if i*1.08>n:
        break
print(":(")
import math
a=int(input())
b=math.ceil(a/1.08)
c=math.floor(a/1.08)
if math.floor(b*1.08)==a:
    print(b)
elif math.floor(c*1.08)==a:
    print(c)
else:
    print(":(")
N = int(input())

X = int(N / 1.08)

ans = ':('
for x in range(X-5, X+6):
    n = int(x * 1.08)
    if n == N:
        ans = x
        break
print(ans)
import math
N = int(input())
if N%27!=26 and N%27!=13:
  print(math.ceil(N/1.08))
else:
  print(':(')
N=input()
N=float(N)
import math
X=math.ceil(N/1.08)
if int(X*1.08)==N:
  print(X)
else:
  print(':(')
n = int(input())

import math

x = math.ceil(n / 1.08)
m = math.floor(x * 1.08)

if m == n:
    print(int(x))
else:
    print(':(')
import math
n = int(input())
for i in range(50000):
  if math.floor(i*1.08)==n:
    print(i)
    exit()
print(':(')
import math
N = int(input())
count = 0
ans = 0
for i in range(N+1):
    money = 0
    money = math.floor(i*1.08)
    if money == N:
        count += 1
        ans = i
        break
if count == 0:
    print(":(")
else:
    print(ans)
n = int(input())
x = int(n / 1.08)

if int(x * 1.08) == n:
    print(x)
elif int((x-1) * 1.08) == n:
    print(x-1)
elif int((x+1) * 1.08) == n:
    print(x+1)
else:
    print(":(")
N = int(input())

for x in range(N+1):
    if int(x*1.08) == N:
        print(x)
        break
else:
    print(':(')
n=int(input())
a=int(n/1.08)
aa=a-1
aaa=a+1
b=int(a*1.08)
bb=int(aa*1.08)
bbb=int(aaa*1.08)
A=[a,aa,aaa]
B=[b,bb,bbb]
f=0
for i in range(3):
  if B[i]==n:
    f=1
    ans=A[i]
    break
if f==0:
  print(":(")
else:
  print(ans)
import sys
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
read = sys.stdin.buffer.read
sys.setrecursionlimit(10 ** 7)

N = int(input())

import math
lower = math.floor(N / 1.08)
upper = math.ceil(N / 1.08)
if math.floor(lower * 1.08) == N:
    print(lower)
elif math.floor(upper * 1.08) == N:
    print(upper)
else:
    print(":(")
n=int(input())
lowx=-(-n*100//108)
highx=-(-(n+1)*100//108)

if lowx<highx:
  print(lowx)
else:
  print(':(')
import math
N = int(input())
for i in range(1,50001):
    if math.floor(i*1.08) == N:
        print(i)
        break
else:
    print(":(")
N=int(input())
for i in range(1,N+1):
    if i*108//100 == N:
        print(i)
        break
else:
    print(":(")
import math


n = int(input())
o = n / 1.080

o_floor = math.floor(o)
o_ceil = math.ceil(o)

if math.floor(o_floor * 1.08) == n:
    print(o_floor)

elif math.floor(o_ceil * 1.08) == n:
    print(o_ceil)

else:
    print(':(')
N = int(input())
for i in range(N+1):
  if int(i*1.08)==N:
    print(i)
    break
else:
  print(":(")
n = int(input())
quo = int(n/1.08)
temp = 0
while temp<= n:
  temp = int(quo*1.08)
  if temp == n:
    print(quo)
    break
  quo = quo+1
if temp > n:
  print(':(')
n=int(input())
for i in range(n+1):
    if int(i*1.08) == n:
        print(i)
        exit()
print(':(')
import math
N=int(input())
x=math.ceil(N/1.08)
if math.floor(x*1.08) == N:
  print(x)
else:
  print(":(")
import math
N=int(input())
X=N/1.08
X=math.ceil(X)
if math.floor(X*1.08)==N:
  print(X)
else:
  print(":(")
n=int(input())
for i in range(50000):
    if(int(i*1.08)==n):
        print(i)
        exit()
print(':(')
n = int(input())

for v in range(int(n//1.08)+2):
    if int(v*1.08) == n:
        print(v)
        exit()
print(':(')
N=int(input())
n=N//1.08
a=int(n*1.08)
b=int((n+1)*1.08)
print(int(n) if a==N else int(n+1) if b==N else ":(")
n = int(input())
a = n//1.08

if int((a-1)*1.08) == n:
  print(int(a-1))
elif int(a*1.08) == n:
  print(int(a))
elif int((a+1)*1.08) == n:
  print(int(a+1))
else:
  print(':(')
a = [int(i*1.08) for i in range(1, 46298)]
n = int(input())
if(n in a):
  print(a.index(n)+1)
else:
  print(":(")
n = int(input())
a = int(n/1.08)
if int(a*1.08) == n:
  print(a)
elif int((a+1)*1.08) == n:
  print(a+1)
else:
  print(':(')
import math

N = int(input())
t = False
for i in range(N * 100, (N + 1) * 100):
    if i % 108 == 0:
        t = True
        break
if t:
    print(math.ceil(N / 1.08))
else:
    print(':(')
N = int(input())
x = N//1.08
y = x+1

if N % 1.08 == 0:
    print(int(x))
else:
    if y * 1.08 >=  N+1 and x * 1.08 < N:
        print(':(')
    else:
        print(int(y))
import math

n = int(input())

price = n / 1.08

if int(math.ceil(price) * 1.08) == n:
	print(math.ceil(price))
elif int(math.floor(price) * 1.08) == n:
	print(math.floor(price))
else:
	print(":(")
import math
n=int(input())
if int(math.ceil(n/1.08)*1.08)==n:
    print(math.ceil(n/1.08))
else:
    print(":(")
#B
import math
n=int(input())
ans=None
for i in range(1,54000):
    if math.floor(i*1.08)==n:
        ans=i
        break
    if i==n-1:
        ans=":("
print(ans)
from math import ceil, floor

def resolve():
  N = int(input())
  tax = 0.08

  if floor(ceil(N/(1+tax))*(1+tax)) == N:
    print(ceil(N/(1+tax)))
  else:
    print(":(")

if __name__ == "__main__":
  resolve()
N = int(input())

Tax = False

for i in range(50000):
    if int(i*1.08) == N:
        Tax = True
        break

if Tax:
    print(i)
else:
    print(':(')
# B - Tax Rate
from math import ceil, floor


def main():
    N = int(input())
    x = ceil(N / 1.08)
    is_possible = floor(x * 1.08) == N
    print(x if is_possible else ":(")


if __name__ == "__main__":
    main()
# B - Tax Rate
ans = ':('
N = int(input())
for X in range(1,50000):
    tmp = int(X*1.08+0.000001)
    if tmp==N:
        ans = X
        break
print(ans)
import math

def main():

    n = int(input())
    tax = 1.08
    
    ans = math.ceil(n / tax)
    ans_check = ans * tax
    if math.floor(ans * tax) == n:
        print(ans)
    else:
        print(":(")
    
if __name__ == "__main__":
    main()
import math
N = int(input())

for i in range(1,46298):
    if math.floor(i*1.08) == N:
        print(i)
        exit()
print(":(")
N = int(input())
import math
X = math.ceil(N/1.08)
if math.floor(X * 1.08) == N:
    print(X)
else:
    print(":(")
price = int(input())

prime_cost = int(price / 1.08)

if (prime_cost * 1.08)//1 == price:
      print(prime_cost)
elif ((prime_cost + 1) * 1.08)//1 == price:
      print(prime_cost + 1)
else:
      print(":(")
N = int(input())
for X in [-int(-N/1.08), int((N+1)/1.08)]:
    if int(X * 1.08) == N:
        print(X)
        exit()
print(":(")
N = int(input())

x = int(N * 100 / 108)

if x * 108 // 100 == N:
  print(x)
elif (x+1) * 108 // 100 == N:
  print(x+1)
else:
  print(':(')
# ####################################################################
# import io
# import sys

# _INPUT = """\
# 1001
# 1079
# 432

# 12 5 2
# cabbabaacaba

# 10 2 3
# abccabaabb
# """
# sys.stdin = io.StringIO(_INPUT)
####################################################################
import sys
def p(*_a):
  return
  _s=" ".join(map(str,_a))
  #print(_s)
  sys.stderr.write(_s+"\n")
####################################################################
yn = lambda b: print('Yes') if b else print('No')
####################################################################
N = int(input())

NO = ":("

a = (N-1) // 1.08

for i in range(100):
  b = a + i
  if int(b * 1.08) == N:
    print( int(b) )
    exit()

print(NO)
N = int(input())
if int(N//1.08 * 1.08) == N:
    print(int(N//1.08))
elif int(-(-N//1.08) * 1.08) == N:
    print(int(-(-N//1.08)))
else:
    print(':(')
N = int(input())
X = int(N/1.08)

if int(X*1.08) == N:
    print(X)
elif int((X+1)*1.08) == N:
    print(X+1)
else:
    print(":(")
n = int(input())
x = int(n / 1.08)

while int(x*1.08) <= n:
    if int(x*1.08) == n:
        print(x)
        break
    else:
        x += 1

if int(x*1.08) > n:
    print(":(")
def hantei(N):
    for i in range(100*N,100*(N+1)):
        if i%108 == 0:
            return(int(i/108))
    return ":("

N = int(input())
print(hantei(N))
n=int(input())
ans=":("

for i in range(1,n+1):
    if int(i*1.08)==n:
        ans=i
print(ans)
from math import floor

def main(N, rate=1.08):
    ans = -1
    for x in range(1, N+1):
        if floor(x * 1.08) == N:
            ans = x
    return ans


if __name__ == "__main__":
    N = int(input())
    ans = main(N)
    print(ans if ans > 0 else ':(')
import math
f = True
N = int(input())
for i in range(N+1):
    if math.floor(i*1.08) == N:
        print(i)
        f = False
        break
if f:
    print(":(")
n = int(input())
x0 = int(n/1.08)
if int(x0*1.08) == n:
    print(x0)
elif int((x0+1)*1.08) == n:
    print(x0+1)
else:
    print(':(')
n = int(input())

xmin = int(n/1.08)
xmax = int((n+1)/1.08)


if n%27 == 0:
  print(xmax)
elif (n+1)%27 == 0:
  print(":(")
elif xmin == xmax:
  print(":(")
else:
  print(xmax)
n = int(input())
for i in range(1,50001):
    if int(i*1.08) == n:
        print(i)
        exit()
print(":(")
import math

N = float(input())
for i in range(50000):
    if math.floor(i * 1.08) == N:
        print(i)
        exit()
print(':(')
# sumitb2019_b_bacha.py
N = int(input())
for i in range(50000):
    if int(i*1.08) == N:
        print(i)
        exit()
print(":(")
n=int(input())
a=int(n/1.08)
z=lambda x:int(x*1.08)
if z(a)==n:
  print(a)
elif z(a+1)==n:
  print(a+1)
else:
  print(":(")
import math
N=int(input())

X_kari = math.ceil(N/1.08)
if int(X_kari * 1.08) == N:
  print(X_kari)
else: print(':(')
N = int(input())
if (N*100)%108 == 0 :
    print(int(N/1.08))
else :
    for i in range(1,100) :
        if (N*100+i) % 108 == 0 :
            print(int((N*100+i)/108))
            break
    else :
        print(":(")
def main():
    from builtins import int, map, list, print
    import sys
    sys.setrecursionlimit(10 ** 6)

    input = sys.stdin.readline
    input_list = (lambda: input().rstrip().split())
    input_number = (lambda: int(input()))
    input_number_list = (lambda: list(map(int, input_list())))

    N = input_number()
    for i in range(50000):
        t = i * 1.08 // 1
        if t == N:
            print(i)
            break
    else:
        print(':(')

if __name__ == '__main__':
    main()
def resolve():
    import math
    n = int(input())
    res = math.ceil(n / 1.08)
    if str(res)[-2:] == '.0':
        print(int(res))
    elif str(res * 1.08).split('.')[0] == str(n):
        print(int(str(res).split('.')[0]))
    else:
        print(':(')

resolve()