Problem:
 Score: 200 points    Problem Statement  Takahashi bought a piece of apple pie at ABC Confiserie. According to his memory, he paid N yen (the currency of Japan) for it.  The consumption tax rate for foods in this shop is 8 percent. That is, to buy an apple pie priced at X yen before tax, you have to pay X \times 1.08 yen (rounded down to the nearest integer).  Takahashi forgot the price of his apple pie before tax, X , and wants to know it again. Write a program that takes N as input and finds X . We assume X is an integer.  If there are multiple possible values for X , find any one of them. Also, Takahashi's memory of N , the amount he paid, may be incorrect. If no value could be X , report that fact.      Constraints   1 \leq N \leq 50000  N is an integer.         Input  Input is given from Standard Input in the following format:  N       Output  If there are values that could be X , the price of the apple pie before tax, print any one of them. If there are multiple such values, printing any one of them will be accepted. If no value could be X , print :( .        Sample Input 1 432      Sample Output 1 400  If the apple pie is priced at 400 yen before tax, you have to pay 400 \times 1.08 = 432 yen to buy one. Otherwise, the amount you have to pay will not be 432 yen.       Sample Input 2 1079      Sample Output 2 :(  There is no possible price before tax for which you have to pay 1079 yen with tax.       Sample Input 3 1001      Sample Output 3 927  If the apple pie is priced 927 yen before tax, by rounding down 927 \times 1.08 = 1001.16 , you have to pay 1001 yen.

Solution (Python):
import math
N = int(input())

X = N/1.08
X = math.floor(X)
flag = True
for i in range(14):
    if N == math.floor((X+i)*1.08):
        print(X+i)
        flag = False
        break
if flag:
    print(":(")

Solution (Python):
N = int(input())
X = N / 1.08
if X == int(X):
    print(int(X))
elif X + 1/1.08 > int(X) + 1:
    print(int(X) + 1)
else:
    print(':(')

Solution (Python):
import collections
import itertools as it
import math
import numpy as np









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

Solution (Python):
def main():
    
    
    N = int(input())
    X = int(N / 1.08)
    flag = False
    for i in [X-1, X, X+1]:
        if int(i*1.08) == N:
            flag = True
            print(i)
            break
    if not flag:
        print(':(')


if __name__ == "__main__":
    main()

Solution (Python):



import math

N = int(input())

X1 = int(N / 1.08)
X2 = X1 + 1

if math.floor(X1 * 1.08) == N:
    print(X1)
elif math.floor(X2 * 1.08) == N:
    print(X2)
else:
    print(":(")

Solution (Python):
import math

n=int(input())

n_lst=[]
x_lst=[]
for i in range(1,50000):
    n_lst.append(i)
    x_lst.append(math.floor(i*1.08))

if n in x_lst:
    print(n_lst[x_lst.index(n)])
else:
    print(':(')

Solution (Python):
import math
n = int(input())

tmp = n//1.08

if math.floor(tmp * 1.08) == n:
    print(int(tmp))
elif math.floor((tmp+1) * 1.08) == n:
    print(int(tmp + 1))
else:
    print(":(")

Solution (Python):
N = int(input())
a = N/1.08
b = int(a)
while(True):
    c = int(b*1.08)
    if c==N:
        print(b)
        exit(0)
    if c>N:
        break
    b+=1
print(':(')

Solution (Python):
if __name__ == '__main__':
    a = int(input())
    ans = 0
    for i in range (50001):
        j = int(i* 1.08)
        if j == a:
            ans = i
            break
        if i == 50000:
            ans = ':('
    print(ans)

Solution (Python):
n= int(input())
if n%27==26 or n%27==13:
    print(":(")
else:
    print(int((n+1)/1.08))

Solution (Python):
n = int(input())
x = int(n / 1.08)
if n == int(x * 1.08):
    print(x)
elif n == int((x + 1) * 1.08):
    print(x + 1)
elif n == int((x - 1) * 1.08):
    print(x - 1)
else:
    print(':(')

Solution (Python):
import math

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

if math.floor(x * 1.08) == n:
    print(x)
else:
    print(':(')

Solution (Python):
n = int(input())

ans = None
for y in range(1, 50001):
    if int(y * 1.08) == n:
        ans = y
        break

if ans is None:
    print(':(')
else:
    print(y)

Solution (Python):
import math
def resolve():
    n = int(input())
    if float.is_integer(n/1.08):
        print(int(n/1.08))
        return None
    ans = math.floor(n/1.08)+1
    if ans < (n+1)/1.08:
        print(int(ans))
    else:
        print(":(")  
resolve()

Solution (Python):
n = int(input())

if int(int((n+1)/1.08)*1.08) == n:
    print(int((n+1)/1.08))
else:
    print(':(')

Solution (Python):
n0 = int(input())
n = n0+0.99
ans = int(n/1.08)


if int(ans*1.08) == n0:
    print(ans)
else:
    print(":(")

Solution (Python):
import math
N = int(input())
flg = 0

ans = 0

for x in range(50000):
	if math.floor(x * 1.08) == N:
		flg = 1
		ans = x
		break
	elif math.floor(x * 1.08) > N:
		break
		
if flg:
	print(ans)
else:
	print(":(")

Solution (Python):
N = int(input())
t = N / 1.08
k = int(abs(t))
if k * 1.08 - N < 1 and k * 1.08 - N >= 0:
  print(k)
elif (k+1) * 1.08 - N < 1 and (k+1) * 1.08 - N >= 0:
  print(k+1)
else:
  print(":(")

Solution (Python):
n = int(input())
a = int(-(-n//1.08))
print(a if int(a*1.08)==n else ':(')

Solution (Python):
import math
n = int(input())
min_n = int(n // 1.08)
max_n = math.ceil(n / 1.08)

for x in range(min_n, max_n+1):
    if math.floor(x * 1.08) == n:
        print(x)
        exit()
print(":(")

Solution (Python):
import math
n = float(input())
ans = n / 1.08
ansu = math.ceil(ans)
ansd = math.floor(ans)
if math.floor(ansu * 1.08) == n:
    print(ansu)
elif math.floor(ansd * 1.08) == n:
    print(ansd)
else:
    print(":(")

Solution (Python):
from math import ceil

N = int(input())
R = 1.08

ans_extax = ceil(N / R)
ans_intax = int(ans_extax * R)

if ans_intax == N:
    print(ans_extax)
else:
    print(":(")

Solution (Python):
N = int(raw_input())
r = 1.08

candidate = int(N/r)

flag = False
max_value = 0
for i in range(-50, 50):
    value = int((candidate + i)*r)
    if value == N:
        if candidate+i > max_value:
            max_value = candidate+i
        flag = True


if flag == True:
    print max_value
else:
    print ":("

Solution (Python):
inpl = lambda: list(map(int,input().split()))
from math import ceil
N = int(input())
X = int(ceil(N * 100 / 108))
M = X * 108 // 100
if M == N:
    print(X)
else:
    print(':(')

Solution (Python):
N=int(input())
X=int(N/1.08)
import math
if math.floor(X*1.08)==N:
  print(X)
  exit()
elif math.floor(X*1.08)<N:
  while math.floor(X*1.08)<N:
    X+=1
else:
  while math.floor(X*1.08)>N:
    X-=1
if math.floor(X*1.08)==N:
  print(X)
else:
  print(':(')

Solution (Python):
import math
n=int(input())
 
for i in range(1,50001):
	if math.floor(i*1.08)==n:
		print(i)
		exit()
 
print(":(")

Solution (Python):
import sys
input = sys.stdin.readline
import math
tax = 1.08
def print_ans(N):
    """Test Case
    >>> print_ans(432)
    400
    >>> print_ans(1079)
    :(
    >>> print_ans(1001)
    927
    """
    X = int(N // tax)
    if N == math.floor(X * tax):
        print(X)
    elif N == math.floor((X + 1) * tax):
        print(X + 1)
    else:
        print(":(")
    
if __name__ == '__main__':
    N = int(input().rstrip())
    print_ans(N)

Solution (Python):
from math import floor


n = int(input())
for i in range(50000):
    if floor(i * 1.08) == n:
        print(i)
        exit()
print(':(')

Solution (Python):
import math

n = int(input())
s = n / 1.08
u = math.floor(s)
l = math.ceil(s)
if math.floor(u * 1.08) == n:
    print(u)
    exit()
elif math.floor(l * 1.08) == n:
    print(l)
    exit()
else:
    print(":(")

Solution (Python):

import math
def main():
    N = int(input())
    tax = 1.08
    price_base = math.floor(N/tax)

    if math.floor((price_base)*tax) == N:
        print(price_base)
        return

    if math.floor((price_base+1)*tax) == N:
        print(price_base+1)
        return
    
    if math.floor((price_base-1)*tax) == N:
        print(price_base-1)
        return
    
    print(':(')
    


if __name__ == "__main__":
    main()

Solution (Python):
n=int(input())
a=n//1.08
from math import floor as f
p=[a,a-1,a+1,a-2,a+2]
c=[]
for i in p:
    if f(i*1.08)==n:
         c.append(i)
if len(c)==0:
    print(":(")
else:
    print(int(c[0]))

Solution (Python):


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

    for Ans in range(N+1):
        Check = int(Ans * 1.08)
        if Check == N:
            print(Ans)
            return

    print(":(")
        


if __name__ == "__main__":
    main()

Solution (Python):
import math
N = int(input())

for i in range(1, N+1):
    if i + math.floor(i * 0.08) == N:
        print(i)
        break
else:
    print(':(')

Solution (Python):
N=int(input())

num=N/1.08

flag1=int(num)
flag2=int(num)+1

if int(flag1*1.08)==N:
    print(flag1)
elif int(flag2*1.08)==N:
    print(flag2)
else:
    print(':(')

Solution (Python):
import math

N = int(input())

f = math.floor(N / 1.08)
c = math.ceil(N / 1.08)

if (math.floor(f * 1.08) == N):
    print(f)
elif (math.floor(c * 1.08) == N):
    print(c)
else:
    print(":(")

Solution (Python):
n=int(input())
for i in range(1,n+1):
    t=int(i*1.08)
    if t==n:
        print(i)
        exit()
print(':(')

Solution (Python):
from math import floor
N = int(input())
for i in range(N+1):
    if floor(i*1.08) == N:
        print(i)
        exit()
print(":(")

Solution (Python):
n = int(input())
f = int(n/1.08)
if int(f*1.08) != n and int((f+1)*1.08) != n:
  print(':(')
elif int(f*1.08) == n:
  print(f)
else:
  print(f+1)

Solution (Python):
n=int(input())

no_tax=[[i,int(i*1.08)] for i in range(1,50001)]

ans=False
for g in range(len(no_tax)):
    if n==no_tax[g][1]:
        ans=True
        break

if ans:
    print(no_tax[g][0])
else:
    print(":(")

Solution (Python):
N = int(input())
flag = False

for i in range(50000):
    if (not flag) and ((i*1.08)//1 == N):
        print(i)
        flag = True

if (not flag):
    print(":(")

Solution (Python):
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(":(")

Solution (Python):
N=int(input())
f=0
for i  in range(50001):
    if int(i*1.08)==N:
        print(i)
        f=1
        break
print(":(" if f==0 else "")

Solution (Python):
n=int(input())
for x in range(50000):
    if int(x * 1.08) == n:
        print(x)
        break
else:
    print(":(")

Solution (Python):
n = int(input())
a = []
flag = 0
for i in range(1,50000):
    b = int(i * 1.08)
    if b == n:
        print(i)
        flag = 1
        break
if flag == 0:
    print(":(")

Solution (Python):

N = int(input())

if N != int((N // 1.08) * 1.08 // 1):
    if N != int((N // 1.08 + 1) * 1.08 // 1):
        print(":(")
    else:
        print(int((N // 1.08 + 1)))
else:
    print(int((N // 1.08)))

Solution (Python):
import math

N=int(input())

S=N*100//108

if math.floor(S*1.08)==N:
    print(S)
elif math.floor((S+1)*1.08)==N:
    print(S+1)
else:
    print(':(')

Solution (Python):
N = int(input())


f0 = int(N / 1.08)
f1 = f0 + 1

if int(f0 * 1.08) == N:
    print(f0)
elif int(f1*1.08) == N:
    print(f1)
else:
    print(":(")

Solution (Python):
X = int(input())
if (X/1.08).is_integer():
  print(int((X/1.08)))
else:
  if int((int(((X/1.08)))+1)*1.08)==X:
    print(int((int(((X/1.08)))+1)))
  else:
    print(":(")

Solution (Python):
import math
N = int(input())

X = math.ceil(N/1.08)



if N == int(X*1.08):
    print(int(X))
else:
    
    print(":(")

Solution (Python):
N = int(input())
X = int(N/1.08)


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(":(")

Solution (Python):
import sys
import math
sys.setrecursionlimit(10**6)

ii = lambda: int(input())
mis = lambda: map(int,input().split())
lmis = lambda: list(mis())
INF = float('inf')

def main():
    n=ii()
    pay=n/1.08
    if int(int(pay)*1.08)==n:
        print(int(pay))
    elif int(math.ceil(pay)*1.08)==n:
        print(math.ceil(pay))
    else:
        print(':(')


if __name__ == "__main__":
    main()

Solution (Python):
import math

N = int(input())

ans = math.ceil(N/1.08)
if (math.floor(ans*1.08) == N):
    print(ans)
else:
    print(":(")

Solution (Python):
n = int(input())
for i in range(1, 50000):
  if int(i * 1.08) == n:
    print(i)
    exit()
print(":(")

Solution (Python):
n = int(input())
if n*100 % 108 ==0:
    print(int(n/1.08))
else:
    x = int(n/1.08)+1
    if int(x*1.08) == n:
        print(x)
    else:
        print(":(")

Solution (Python):
import sys
input = sys.stdin.readline

_n = int(input())


def chker(n):
    nontax1 = int(n / 1.08)
    nontax2 = nontax1 + 1

    if int(1.08 * nontax1) == n:
        print(nontax1)
    elif int(1.08 * nontax2) == n:
        print(nontax2)
    else:
        print(':(')


chker(_n)

Solution (Python):
N = int(input())

k = N // 1.08
k = int(k)
if int(k * 1.08) == N:
    print(k)
elif int((k + 1) * 1.08) == N:
    print(k + 1)
else:
    print(':(')

Solution (Python):
import math

n = int(input())
x_min = int(n/1.08)
x_max = int((n+1)//1.08+1)

ans = 0
for i in range(x_min, x_max+1):
  if math.floor(i*1.08) == n:
    ans=i
    print(i)
    break

if ans==0:
  print(':(')

Solution (Python):
NtoX = {}
for i in range(1, 54001):
    NtoX[i] = -1
for i in range(1, 50001):
    n = int(i*1.08)
    NtoX[n] = i
    
N = int(input())
print(":(" if NtoX[N]==-1 else NtoX[N])

Solution (Python):
n=int(input())
lo=0 
ans=":("
hi=n+4 
while lo<=hi: 
    mi=(lo+hi)>>1 
    if int(mi*(1.08))==n:
        ans=mi 
        break 
    elif mi*(1.08)>n:
        hi=mi-1 
    else:
        lo=mi+1 
print(ans)

Solution (Python):
import math

n = int(input())

x = math.ceil(n / 1.08)
if math.floor(x * 1.08) == n:
  print(x)
else:
  print(':(')

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

Solution (Python):
n = int(input())
for x in range(n+1):
    if n == x*1.08//1:
        print(x)
        exit()

print(':(')

Solution (Python):
N = int(input())
X = N//1.08
X = int(X)
while X*1.08 <= N+1:
    if int(X*1.08) == N :
        print(int(X))
        exit()
    else:
        X += 1
print(":(")

Solution (Python):
N = int(input())
for i in range(1,50001):
    if int(i * 1.08) == N:
        print(i)
        exit(0)
print(':(')

Solution (Python):
import math
import sys
n=int(input())
x=int(n/1.08)
for i in [x-1,x,x+1]:
    if math.floor(i*1.08)==n:
        print(i)
        sys.exit()
print(":(")

Solution (Python):
n = int(input())
for i in range(50000):
  if int(i * 1.08) == n:
    print(i)
    exit()
print(":(")

Solution (Python):


N = int(input())

origin = int(N / 1.08)

if int((origin+1)*1.08) == N:
    print(origin+1)
elif int(origin*1.08) == N:
    print(origin)
else:
    print(':(')

Solution (Python):
import math
N=int(input())

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

Solution (Python):
N = int(input())
a = N / 1.08
b = (N + 1) / 1.08
c = int(a)
d = int(a) + 1
if a <= c and c < b:
    print(c)
elif a <= d and d < b:
    print(d)
else:
    print(":(")

Solution (Python):
N = int(input())

res = ':('

for X in range(1,N+1):
    temp = int(X * 1.08)
    if temp == N:
        res = X
        break 

print(res)

Solution (Python):
n = int(input())
for x in range(n+1):
    if x*1.08//1 == n:
        print(x)
        break
else:
    print(':(')

Solution (Python):

from heapq import heappush, heappop, heapify
from collections import deque, defaultdict, Counter
import itertools
from itertools import permutations, combinations
import sys
import bisect
import string
import math
import time
from fractions import gcd



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

    

    for i in range(100000):
        if N == int(i * 1.08):
            print(i)
            return

    print(':(')


if __name__ == '__main__':
    main()

Solution (Python):
import math
import sys
N = int(input())

X_floor = math.floor(N / 1.08)
X_ceil = math.ceil(N / 1.08)

if int(X_floor * 1.08) == N:
    print(X_floor)
    sys.exit()
if int(X_ceil * 1.08) == N:
    print(X_ceil)
    sys.exit()

print(":(")

Solution (Python):
a = int(input())
tmp = a/1.08
if int(int(tmp) * 1.08) == a:
    print(int(tmp))
elif int(int(tmp+1) * 1.08) == a:
    print(int(tmp)+1)
else:
    print(':(')

Solution (Python):
n = int(input())
for i in range(1, 50001):
    with_tax = int(i * 1.08)
    if with_tax == n:
        print(i)
        exit()
print(':(')

Solution (Python):

from collections import defaultdict,deque
from heapq import heappush, heappop
from bisect import bisect_left, bisect_right
import sys, random, itertools, math
sys.setrecursionlimit(10**5)
input = sys.stdin.readline
sqrt = math.sqrt
def LI(): return list(map(int, input().split()))
def LF(): return list(map(float, input().split()))
def LI_(): return list(map(lambda x: int(x)-1, input().split()))
def II(): return int(input())
def IF(): return float(input())
def LS(): return list(map(list, input().split()))
def S(): return list(input().rstrip())
def IR(n): return [II() for _ in range(n)]
def LIR(n): return [LI() for _ in range(n)]
def FR(n): return [IF() for _ in range(n)]
def LFR(n): return [LI() for _ in range(n)]
def LIR_(n): return [LI_() for _ in range(n)]
def SR(n): return [S() for _ in range(n)]
def LSR(n): return [LS() for _ in range(n)]
mod = 1000000007
inf = float('INF')


def solve():
    x = II()
    for i in range(50000):
        if int(i * 1.08) == x:
            print(i)
            return
    print(":(")



if __name__ == '__main__':
    solve()

Solution (Python):
N = int(input())
import math
price = ':('
for i in range(50001):
  X = i*1.08
  if math.floor(X) == N:
    price = i
    break
print(price)

Solution (Python):
n=int(input())
nn=n/1.08
s=':('
def ans():
  m=int(nn)
  for i in range(m-5,m+6):
    if int(i*1.08)==n:
      print(i)
      return
  print(s)
ans()

Solution (Python):
n = int(input())
for i in range(1,50001):
    if int(i * 1.08) == n:
        print(i)
        exit()
print(":(")

Solution (Python):
import math

N = int(input())
low = math.ceil(N / 1.08)
up = math.floor(N / 1.08)

if math.floor(low * 1.08) == N:
    print(low)
elif math.floor(up * 1.08) == N:
    print(up)
else:
    print(':(')

Solution (Python):
import math


N = int(input())

ans = N / 1.08
tmp = math.ceil(ans)

tmp2 = math.floor(tmp*1.08) 

if int(tmp2) == N:
    print(int(tmp))

else:
    print(":(")

Solution (Python):
n = int(input())

ans = 0
for i in range(1, n+1):
  if int(i * 1.08) == n:
    ans = i
    break

if ans == 0:
  print(':(')
else:
  print(ans)

Solution (Python):
import math
n=int(input())

for i in range(50000):
  if math.floor(i*1.08)==n:
    print(i)
    exit()
print(':(')

Solution (Python):
import math
import sys
n = int(input())
ans = math.floor(n/1.08)
for i in range(ans,ans+2):
    a = math.floor(i*1.08)
    if a == n:
        print(i)
        sys.exit()
print(':(')

Solution (Python):
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(":(")

Solution (Python):
import sys
N = int(input())
for x in range(1,50000):
    if int(x * 1.08) == N:
        print(x)
        sys.exit()
print(":(")

Solution (Python):
def main():
    n = int(input())
    ans = 0
    tmpls = []
    for i in range(1,50001):
        tmp = int(i*1.08)
        tmpls.append(tmp)
    for i, p in enumerate(tmpls, 1):
        if n == p:
            ans = i
            break
    if ans == 0:
        print(":(")
    else:
        print(ans)

if __name__ == "__main__":
    main()

Solution (Python):
N = int(input())
X = N/1.08
m = int(X)
ans = ':('
for i in [m-2,m-1,m,m+1,m+2]:
    if int(i*1.08)==N:
        ans = i
print(ans)

Solution (Python):


n=int(input())
ans=":("

for i in range(50000):
    if int(i*1.08)==n:
        ans=i

print(ans)

Solution (Python):




n = int(input())


val_d = n / 1.08
val_i = int(n / 1.08)

if val_d == val_i:
    ans = val_i
else:
    if int((val_i + 1) * 1.08) == n:
        ans = val_i + 1
    else:
        ans = ":("


print(ans)

Solution (Python):
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(':(')

Solution (Python):
import math
N = int(input())
ans = N / 1.08
ans = math.floor(ans)
if ans * 1.08 == N:
    print(ans)
elif math.floor((ans+1) * 1.08) == N:
    print(ans+1)
else:
    print(':(')

Solution (Python):
import math

N = int(input())
ERR = ':('

answer = -1
for i in range(1, N + 1):
    if N == math.floor(i * 1.08):
        answer = i

if answer == -1:
    print(ERR)
else:
    print(answer)

Solution (Python):
import math
N = int(input())
for  i in range(1,N+1):
    if  math.floor(i * 1.08) == N:
        print(i)
        exit()
print(":(")

Solution (Python):
n = int(input())

x = [i for i in range(1,50001)]
y = [int(xi * 1.08) for xi in x]

if n in y:
    print(x[y.index(n)])
else:
    print(':(')

Solution (Python):
n = int(input())

for i in range(50000):
    a = int(i*1.08)
    if a == n:
        print(i)
        exit()

print(':(')

Solution (Python):
def ans(N):
  if N < 13:
    return N
  high = N
  low = 0
  while 1 < high - low:
    med = (high + low) // 2
    p = int(med * 1.08)
    if p == N:
      return med
    if p < N:
      low = med
    if N < p:
      high = med
  return ':('
N = int(input())
print(ans(N))

Solution (Python):
n=int(input())

x = int(n / 1.08)

for i in range(x,x+4000):
  if int(i * 1.08) == n:
    print(i)
    exit()
print(":(")

Solution (Python):
def num():
    return int(input())

def nums():
    return list(map(int,input().split()))


"""
M1,D1 = nums()
M2,D2 = nums()
print(int(M1 != M2))
"""

import math
N = num()
without_tax = N / 1.08
if int(int(without_tax) * 1.08) == N:
    print(int(without_tax))
elif int(math.ceil(without_tax) * 1.08) == N:
    print(math.ceil(without_tax))
else:
    print(":(")

Solution (Python):
import math

N = int(input())
X = math.floor(N/1.08)
X_list = [X-3, X-2, X-1, X, X+1, X+2, X+3]

for x in X_list:
    if(math.floor(x*1.08) == N):
        print(x)
        exit()
print(":(")

Solution (Python):
N = int(input())

ans = 100000

for i in range(50000):
    Z = int(i * 1.08)
    if Z == N :
        ans = i

if ans == 100000:
    print(':(')
else:
    print(ans)

Solution (Python):
n = int(input())
for i in range(1,50001):
    if int(i*1.08) == n:
        print(i)
        exit(0)
    else:
        pass
print(':(')

Solution (Python):
import math

n = int(input())
x = math.ceil(n/1.08)
_n = int(x*1.08)

if n == _n:
    print(x)
else:
    print(':(')

Solution (Python):
import math

n = int(input())

n2 = int(n // 1.08)

if math.floor(n2*1.08) == n:
	print(n2)
elif math.floor((n2-1)*1.08) == n:
	print(n2-1)
elif math.floor((n2+1)*1.08) == n:
	print(n2+1)
else:
	print(":(")

Solution (Python):


import math
import itertools


N = int(input())



X = math.ceil(N/1.08)

if math.floor(X*1.08) == N :
  print (X)
else :
  print (":(")

Solution (Python):
import math
import sys
n=int(input())

for i in range(1,n+1):
    a=math.floor(i*1.08)
    if n == a:
        print(i)
        sys.exit()
print(":(")

Solution (Python):
N = int(input())
X1 = N //1.08
X2 = X1 + 1

if X1 * 1.08 // 1 == N:
    print(int(X1))
elif X2 * 1.08 //1 == N:
    print(int(X2))
else:
    print(':(')

Solution (Python):
n = int(input())

a = round(n / 1.08)
flag = 0
ans = 0
for i in range(a-2, a+3):
    if i + int(i * 0.08) == n:
        ans = i
        flag = 1
        break

if n < 13:
    print(n)
elif flag:
    print(ans)
else:
    print(':(')

Solution (Python):
n = int(input())

ans = ":("
candidate = [ (i, int(i*1.08)) for i in range(1,n+1) ]
candidate_2 = [ i[1] for i in candidate ]

if n in candidate_2:
    ans = candidate[candidate_2.index(n)][0]
print(ans)

Solution (Python):
import math
TAX = 1.08
N = int(input())
num = N / TAX
numf = math.floor(num)
numc = math.ceil(num)
if math.floor(numf * TAX) == N:
    print(numf)
elif math.floor(numc * TAX) == N:
    print(numc)
else:
    print(':(')

Solution (Python):
N=int(input())
if int(N//1.08*1.08)==N:
    print(int(N//1.08))
elif int((N//1.08+1)*1.08)==N:
    print(int((N//1.08+1)))
else:
    print(":(")

Solution (Python):

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

Solution (Python):

import math
N = int(input())

q, mod = divmod(N*100, 108)

if math.floor(q*1.08) == N:
  print(q)
elif math.floor((q+1)*1.08) == N:
  print(q+1)
else:
  print(":(")

Solution (Python):
N=int(input())
l=N*100//108
stp=0
for i in range(2):
  if (l+i)*108//100==N:
    print(l+i)
    stp=1
    break
if stp==0:
  print(':(')

Solution (Python):
def solve():
    N = int(input())
    ans = N / 108 * 100

    if int(int(ans)*1.08) == N:
        print(int(ans))
    elif int(int(ans+1)*1.08) == N:
        print(int(ans+1))
    else:
        print(':(')


if __name__ == '__main__':
    solve()

Solution (Python):


''' 
------------------------
author : iiou16
------------------------
'''
import math


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

    _ans = math.floor(N / 1.08)
    if math.floor(_ans * 1.08) == N:
        print(int(_ans))
    elif math.floor((_ans + 1) * 1.08) == N:
        print(int(_ans + 1))
    else:
        print(":(")

if __name__ == '__main__':
    main()

Solution (Python):
import math
N = int(input())

n = math.floor(N/1.08)

if math.floor(n*1.08) == N: print(n)
elif math.floor((n+1)*1.08) == N: print(n+1)
else: print(":(")

Solution (Python):
N = int( input() )

cnt = 0




for i in range( 50000 ):
  if( int(i * 1.08) == N  ):
    cnt = i
    
if( cnt == 0):
  print(":(")
else:
  print( cnt )

Solution (Python):
import math
N = int(input())

ans = N * 100 / 108


if int(math.ceil(ans)*1.08) == N:
    print(math.ceil(ans))
else:
    print(":(")

Solution (Python):
n = int(input())
a = (n + 0.5) / 1.08
b = n / 1.08

ans = -1
for i in range(int(b)-2,int(a)+2):
    if n <= i*1.08 < n+1:
        ans = i
        break
if ans == -1:
    print(":(")
else:
    print(ans)

Solution (Python):

from math import ceil,floor
n = int(input())
a_upper = ceil(n/1.08)
a_lower = floor(n/1.08)

if a_upper == a_lower:
    print(a_upper)
else:
    if floor(a_upper*1.08) == n:
        print(a_upper)
    elif floor(a_lower*1.08) == n:
        print(a_lower)
    else:
        print(":(")

Solution (Python):
N = int(input())
flag=False

for i in range(50000):
  if int(i*1.08) ==N:
    print(i)
    flag=True
    break
    
if flag==False:
  print(":(")

Solution (Python):
def two_int():
    N, K = map(int, input().split())
    return N,K

def one_int():
    return int(input())

def one_str():
    return input()

def many_int():
    return list(map(int, input().split()))

N=one_int()

flg=True
for i in range(1,N+1 ):
    if int(i*1.08) == N:
        print(i)
        flg=False
        break
if flg:
    print(":(")

Solution (Python):
import math

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

    
    

    for i in range(1, N+100):
        cost = math.floor(i * 1.08)
        if cost == N:
            print(i)
            exit()
    print(':(')


if __name__ == "__main__":
    main()

Solution (Python):
import math
n = int(input())
check = ":("
for i in range(50000):
  if math.floor(i * 1.08) == n:
    check = i
    break
print(check)

Solution (Python):

N = int(input())
import sys
import math
for i in range(N+1):
    if math.floor(i*1.08)==N:
        print (i)
        sys.exit()
print(':(')

Solution (Python):
N = int(input())

sp_n = int(N / 1.08)

if int(sp_n * 1.08) == N:
    print(sp_n)
elif int((sp_n+1) * 1.08) == N:
    print(sp_n + 1)
else:
    print(':(')

Solution (Python):
n = int(input())
res = ":("
for i in range(1, n+1):
    if(int(i * 1.08) == n): 
        res = i
        break
print(res)

Solution (Python):
import math
N = int(input())
for i in range(1,50001):
  if math.floor(i*1.08) == N:
    print(i)
    exit()
else:
  print(":(")

Solution (Python):
n = int(input())

zei = 1.08
result = int(n / zei)
if int(result*zei) == n:
    print(result)
    exit()
big = int(result*zei) > n
while True:
    if big:
        result -=1
    else:
        result +=1
    if int(result*zei) == n:
        print(result)
        exit()
    if big != (int(result*zei) > n):
        print(":(")
        exit()

Solution (Python):
num = int(input())
tax_price_list = [int(num*1.08) for num in range(num+1)]

if num in tax_price_list:
    print(tax_price_list.index(num))
else:
    print(':(')

Solution (Python):
N = int(input())

sho, mod = divmod(N , 1.08)

for p in [sho - 1, sho, sho + 1]:
    price = int(int(p) * 1.08)
    if price == N:
        print(int(p))
        exit(0)
    else:
        pass

print(":(")

Solution (Python):
n = int(input())
x=-(-n//1.08)
if(int(x*1.08)==n):
    print(int(x))
else:
    print(":(")

Solution (Python):
import math
n = int(input())
a = math.ceil(n / 1.08)
print(a if math.floor(a * 1.08) == n else ":(")

Solution (Python):
n = int(input())
v = int(-(-n//1.08))
print(v if int(v*1.08)==n else ':(')

Solution (Python):
import sys
import math

input = sys.stdin.readline

N = int(input())

large = (N+1)/1.08
small = N/1.08

ans = math.ceil(small)
if ans>=large: ans = ':('

print(ans)

Solution (Python):


N = int(input())

tmp = int(N/1.08)

ans = ":("
for i in range(5):
    if int((tmp-2+i)*1.08)==N:
        ans = tmp-2+i
        break
    
print(ans)

Solution (Python):
import math

n = int(input())
x = math.ceil(n / 108 * 100)

if int(x * 1.08) == n:
    print(x)
else:
    print(":(")

Solution (Python):
n = int(input())

shousuu = (n / 1.08) // 1
sita = int(shousuu - 2)
ue = int(shousuu + 2)

for i in range(sita, ue+1):
    if (i * 1.08) // 1 == n:
        print(i)
        exit()

print(':(')

Solution (Python):
n = int(input())

k = n*100/108
k = int(k)

ans = ":("
for i in range(k-1,k+2):
  if n==int(i*1.08):
    ans = i
print(ans)

Solution (Python):
import math

n = int(input())

kirisute = math.floor(n/1.08)
kiriage = math.ceil(n/1.08)




if math.floor(kiriage*1.08) == n:
    print(kiriage)
elif math.floor(kirisute*1.08) == n:
    print(kirisute)
else:
    print(":(")

Solution (Python):
n = int(input())
for i in range(50000):
    p = int(i*0.08)+i
    if p == n:
        print(i)
        break
    if p > n:
        print(":(")
        break

Solution (Python):
n = int(input())
ans = -(-n//1.08)
if int(ans*1.08) == n:
    print(int(ans))
else:
    print(':(')

Solution (Python):
import math
n = int(input())
a = n / 1.08
if int(math.floor(a)*1.08) == n:
    print(math.floor(a))
elif int(math.ceil(a)*1.08) == n:
    print(math.ceil(a))
else:
    print(':(')

Solution (Python):
N = int(input())

is_impossible = True

for i in range(1, 50001):
    if N == int(i * 1.08):
        print(i)
        is_impossible = False

if is_impossible:
    print(":(")

Solution (Python):
n = int(input())
d = n // 1.08
u = (n+1) // 1.08
if int(d*1.08) == n:
    print(int(d))
elif int(u*1.08) == n:
    print(int(u))
else:
    print(":(")

Solution (Python):
from math import ceil

N=int(input())
X=ceil(N/1.08)

if (X*1.08)//1==N:
    print(X)
else:
    print(":(")

Solution (Python):
import sys
MAX_INT = int(10e15)
MIN_INT = -MAX_INT
mod = 1000000007
sys.setrecursionlimit(1000000)
def IL(): return list(map(int,input().split()))
def SL(): return input().split()
def I(): return int(sys.stdin.readline())
def S(): return input()

N = I()

for i in range(50001):
  if int(i * 1.08) == N:
    print(i)
    break
else:
  print(":(")

Solution (Python):
N=int(input())
if (N*100)%108==0:
  print(int(N/1.08))
else:
  X=int((N+1)/1.08)
  if int(X*1.08)==N:
    print(X)
  elif int((X-1)*1.08)==N:
    print(X-1)
  else:
    print(":(")

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