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())

m = math.floor(N / 1.08)
M = math.ceil(N / 1.08) + 1

for t in range(m, M):
    if math.floor(t * 1.08) == N:
        print(t)
        quit()
print(":(")

Solution (Python):
import sys

sys.setrecursionlimit(10 ** 6)
int1 = lambda x: int(x) - 1
p2D = lambda x: print(*x, sep="\n")
def MI(): return map(int, sys.stdin.readline().split())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]

def main():
    n=int(input())
    floor=n*100//108
    ceil=(n*100+107)//108
    if floor*108//100==n:
        print(floor)
    elif ceil*108//100==n:
        print(ceil)
    else:print(":(")
main()

Solution (Python):
n = int(input())
c = n // 1.08
while int(c * 1.08) < n:
    c += 1
if int(c * 1.08) == n:
    print(int(c))
else:
    print(':(')

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

for i in range(50000):
  money = i * 1.08
  money = int(money)
  if money == N:
    print(i)
    exit()

print(":(")

Solution (Python):
N=int(input())
if N%27==13 or N%27==26:
  print(':(')
elif N%27 == 0:
    print((N*50)//54)
else:
    print(((N*50)//54)+1)

Solution (Python):
import math

n = input()
n = int(n)

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

x = math.ceil(a)

if x >= b:
  print(":(")
else:
  print(x)

Solution (Python):
import numpy as np
N = int(input())
X1 = N//1.08
X2 = (N+1)//1.08
if (int(X1) == int(X2)) and (int(X1)*1.08!=N):
  print(":(")
else:
  print(int(X2))

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

Solution (Python):
import math

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

Solution (Python):
import math


total = int(input())

without_tax = math.ceil(total * 100 / 108)
with_tax = math.floor(without_tax * 1.08)

if with_tax != total:
    print(":(")
    exit(0)

print(without_tax)

Solution (Python):
n=int(input())
for i in range(50001): 
    if int(i*1.08)==n: 
        print(i) 
        break 
    elif i==50000: 
        print(':(') 
        break

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

i = 0
ans = ':('

while i < 50000:
  if int(i * 1.08) == n:
    ans = i
    break
  else:
    i += 1

print(ans)

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

for x in range(int(N/1.08), N+1):
  if int(x*1.08) == N:
    print(x)
    break
else:
  print(':(')

Solution (Python):
from math import floor
n = int(input())
noTax = n/1.08

noTax = floor(noTax)




if floor(noTax * 1.08) == n:
    print(floor(noTax))
elif floor((noTax + 1) * 1.08) == n:
    print(noTax + 1)
else:
    print(":(")

Solution (Python):
n = int(input())
if n%1.08 == 0:
    print(int(n//1.08))
else:
    if (n+1)%1.08 == 0:
        print(':(')
        
    elif (n+1)//1.08 == n//1.08:
        print(':(')
    else:
        print(int((n+1)//1.08))

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

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

Solution (Python):
import math

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

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

Solution (Python):

import math
a = int(input())


ans = a/1.08

if int(math.floor(ans)*1.08) == a:
    ans = math.floor(ans)
elif int(math.ceil(ans)*1.08) == a:
    ans = math.ceil(ans)
else:
    ans = ":("

print(ans)

Solution (Python):
import math
N = int(input())
done = False
for i in range(N + 1):
    if math.floor(i * 1.08) == N:
        print(i)
        done = True
        break
        
if not done:
    print(":(")

Solution (Python):
n = int(input())
rate = 1.08

for i in range(max(n - 13, 0) + 1, n + 13 + 1):
  ans = int(i / rate)
  if int(ans * rate) == n:
    print(ans)
    break
  if i == n + 13 :
    print(":(")
    break

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

import math
ans1 = math.floor(ans)
ans2 = math.ceil(ans)

if math.floor(ans1*1.08) == n or math.floor(ans2*1.08) == n:
	if math.floor(ans1*1.08) == n:
		print(ans1)
	else:
		print(ans2)
else:
	print(":(")

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

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

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

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):
N = int(input())
for i in range(1, N+1):
    if N <= i * 1.08  < N + 1:
        print(i)
        exit()
print(":(")

Solution (Python):
from math import ceil, floor
N = int(input())
f = N / 1.08
f_c = ceil(f)
f_f = floor(f)

if floor(f_c *1.08) == N:
    print(f_c)
elif floor(f_f * 1.08) == N:
    print(f_f)
else:
    print(':(')

Solution (Python):

import math

n = int(input())
max_x = (n + 1) / 1.08
min_y = n / 1.08

ans = [i for i in range(math.ceil(min_y), math.ceil(max_x))]
if len(ans) == 0:
	print(":(")
else:
	print(ans[0])

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

for i in range(1, 50001):
    if (i * 1.08) // 1 == n:
        print(i)
        break
    elif i == 47000:
        print(":(")

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

X = int(N * 100 / 108)-1

while True:
  if int(X * 1.08) == N:
    print(X)
    break
  if int(X * 1.08) >= N+1:
    print(":(")
    break
  X += 1

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

x = int(N//1.08)
xx = int(x + 1)

if (int(x * 1.08) == N):
    print(x)
elif (int(xx * 1.08) == N):
    print(xx)
else:
    print(":(")

Solution (Python):

from sys import stdin
import math


def solve(tc):
    n = int(stdin.readline().strip())
    x = n / 1.08
    if int(math.floor(x)*1.08)==n:
        print(int(x))
        return
    if int(math.ceil(x)*1.08)==n:
        print(int(x+1))
        return
    print(":(")


LOCAL_TEST = not __debug__
if LOCAL_TEST:
    infile = __file__.split('.')[0] + "-test.in"
    stdin = open(infile, 'r')

tcs = (int(stdin.readline().strip()) if LOCAL_TEST else 1)
tc = 1
while tc <= tcs:
    solve(tc)
    tc += 1

Solution (Python):
N = int(input())
import math
def tax(N):
    x = N / 1.08
    if math.floor(math.floor(x) * 1.08) == N:
        print(math.floor(x))
    elif math.floor(math.ceil(x) * 1.08) == N:
        print(math.ceil(x))
    else:
        print(':(')
tax(N)

Solution (Python):
import math

N = int(input())
flag = 0

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

print(i if flag == 1 else ':(')

Solution (Python):
def main():
    n = int(input())
    a = int(n / 1.08)
    b = a + 1
    if int(a * 1.08) == n:
        print(a)
    elif int(b * 1.08) == n:
        print(b)
    else:
        print(':(')


if __name__ == '__main__':
    main()

Solution (Python):
from math import ceil, floor

n = int(input())

x = n / 1.08

if x % 1 == 0:
    print(int(x))
    exit()

if n == floor(ceil(x) * 1.08):
    print(ceil(x))
    exit()
   
print(':(')

Solution (Python):
from pprint import pprint
import sys


def solve(n):
    for x in range(50001):
        if int(x * 1.08) == n:
            print(x)
            return
        elif x >= n:
            print(":(")
            return
    print(":(")
    

if __name__ == "__main__":
    n = int(sys.stdin.readline().strip())
    solve(n)

Solution (Python):
X = int(input())
flag = False
ans = 0
for i in range(X+1):
    if(int(i * 1.08) == X):
        ans = i
        flag = True

if flag:
    print(ans)
else:
    print(":(")

Solution (Python):

N = int(input())

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

Solution (Python):
from sys import stdin


def main():
    input = lambda: stdin.readline()[:-1]
    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(':(')


main()

Solution (Python):
import math

n=int(input())
check=0
for x in range(1,50001):
    if math.floor(x*1.08)==n:
        check=1
        ans=x
        break
print(ans if check==1 else ":(")

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

n = int(input())

ls_x = []
ls_x.append( int(n/1.08) )
ls_x.append( int(n/1.08) + 1 )



for x in ls_x:

    y = int(x*1.08)
    

    if y==n:
        print(x)
        exit()
    elif y<(n+1) and y>n:
        print(x)
        exit()

print(":(")
exit()

Solution (Python):
A=int(input())
B=(A*100)//108

if((((B*1.08)//1)==A)):
    print(B)
elif((((B+1)*1.08)//1)==A):
    print(B+1)
else:
    print(":(")

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

k = m/1.08
m1 = math.ceil(k)
m2 = math.floor(k)

if int(m1 * 1.08) == m:
    print(m1)
elif int(m2 * 1.08) == m:
    print(m2)
else:
    print(":(")

Solution (Python):
import sys
N = int(input())
if N <= 12:
    print(N)
    sys.exit()
else:
    for i in range(N):
        if int(i * 1.08) == N:
            print(i)
            sys.exit()
        else:
            None
    print(":(")

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

x = N / 1.08

for i in range(int(x) - 2, int(x) + 3):
    if int(i * 1.08) == N:
        print(i);
        exit()

print(":(");

Solution (Python):
n = int(input())
x = n / 1.08

x_int = int(x)

while int(x_int * 1.08) < n:
  x_int += 1
  
if int(x_int * 1.08) == n:
  print(x_int)
else:
  print(':(')

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

beforeTax = math.floor(n / 1.08)
afterTax = lambda x: math.floor(x * 1.08)

if n == afterTax(beforeTax):
    print(beforeTax)
elif n == afterTax(beforeTax+1):
    print(beforeTax+1)
else:
    print(':(')

Solution (Python):
import math
import sys

N = int(input())

X2 = math.floor(N / 1.08)
X1 = X2 - 1
if X1 < 0:
    X1 = 0
X3 = X2 + 1
if math.floor(X1 * 1.08) == N: 
    print(X1)
elif  math.floor(X2 * 1.08) == N:
    print(X2)
elif  math.floor(X3 * 1.08) == N:
    print(X3)
else:
    print(":(")

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

Solution (Python):
n=int(input())
import math
for i in range(1,46300):
	p=math.floor(i*1.08)
	if p==n:
	    print(i)
	    exit()
print(":(")

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

ans = 0
for i in range(1, N+1):
    if int(i * 1.08) < N:
        continue
    elif int(i * 1.08) == N:
        ans = i
        break
    else:
        break

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

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):
import math
import sys
n = int(input())
end = int(n / 1.08) + 1

for i in reversed(range(end-2, end+1)):
    x = math.floor(i * 1.08)
    if x == n:
        print(i)
        sys.exit()

print(":(")

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

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


price = math.ceil((N/1.08))


if N == (math.floor(price*1.08)):
    print(price)
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):
import math,sys
N=int(input())
min=math.ceil(N/1.08)
max=math.ceil((N+1)/1.08-10**-9)
if min>=max:
  print(":(")
  sys.exit()
print(min)

Solution (Python):
n = int(input())
ans = 0
for x in range(1,50000):
    y = int(x*1.08)
    if y == n:
        ans = x
        break
if ans == 0:
    print(':(')
else:
    print(x)

Solution (Python):
N=int(input())
a=N/1.08
b=(N+1)/1.08
for i in range(50001):
  if a <= i < b:
    print(i)
    exit()
print(':(')

Solution (Python):
N = int(input())
X = int(N / 1.08)
flag = False
if int(X*1.08) == N:
    flag = True
    ans = X
elif int((X+1)*1.08) == N:
    flag = True
    ans = X + 1
if flag:
    print(ans)
else:
    print(':(')

Solution (Python):
import math


N = int(input())

for i in range(1, 50001):
    num = math.floor(i * 1.08)
    if N == num:
        print(i)
        break
    elif num > N:
        print(":(")
        break

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

ans = round(N / 1.08)
b = N / 1.08 - int(N / 1.08)
if b < 0.08 / 1.08 and 0 < b:
    print(":(")
else:
    if not int(ans*1.08) == N:
        print(ans + 1)
    else:
        print(ans)

Solution (Python):
import math
N = int(input())
X = N / 1.08
X = int(X)
X2 = X - 1
X3 = X + 1





if N == math.floor(X * 1.08):
    print(int(X))
elif N == math.floor(X2 * 1.08):
    print(int(X2))
elif N == math.floor(X3 * 1.08):
    print(int(X3))
else:
    print(":(")

Solution (Python):
import math

N = int(input())

for x in range(1, 50000):
  test = math.floor(x * 1.08)
  if test == N:
    print(x)
    exit()
  if test > N or test == 50000:
    print(':(')
    exit()

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

cand = int(n/1.08)
flag = 0

for i in range(100):
  if int((cand-50+i)*1.08) == n:
    print(cand-50+i)
    flag = 1
    break

if flag == 0:
  print(":(")

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


def main():
    sc = Scan()
    N = sc.intarr()[0]
    for i in range(50000):
        inTax = int(i * 1.08)
        if inTax < N:
            continue
        elif inTax == N:
            print(i)
            return
        elif inTax > N:
            print(":(")
            return


class Scan():

    def intarr(self):
        line = input()
        array = line.split(' ')
        num_array = [int(n) for n in array]
        return num_array

    def intarr_ver(self, n):
        return [int(input()) for _ in range(n)]

    def strarr(self):
        line = input()
        array = line.split(' ')
        array[-1] = array[-1].strip('\n')
        return array


def display(array):
    for a in range(len(array)):
        if len(array) - a != 1:
            print(array[a], end=' ')
        else:
            print(array[a])


main()

Solution (Python):

import sys
import math
from bisect import bisect_left
from bisect import bisect_right
import collections
import copy
import heapq
from collections import defaultdict
from heapq import heappop, heappush
import itertools
input = sys.stdin.readline






















def inputInt(): return int(input())
def inputMap(): return map(int, input().split())
def inputList(): return list(map(int, input().split()))

def main():
	N = inputInt()

	ans = -(-N // 1.08)
	ans2 = N / 1.08

	

	if ans2.is_integer():
		print(int(ans))
	else:
		tmp = ans2 - int(ans2)
		if tmp < 0.1:
			print(":(")
		else:
			print(int(ans))







if __name__ == "__main__":
	main()

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())

moto = n//1.08

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

Solution (Python):
def main():

    n = int(input())

    ans = n / 1.08

    ans_int = int(ans)
    

    if int(ans_int * 1.08) == n:
        print(str(ans_int))
    elif int((ans_int+1) * 1.08) == n:
        print(str(ans_int+1))
    else:
        print(':(')




if __name__ == '__main__':
    main()

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

Solution (Python):
import sys
a = int(input())
for x in range(10**5 + 100):
    if int(x*1.08) == a:
        print(x)
        sys.exit()
print(':(')

Solution (Python):
import math
n = int(input())
for i in range(n+1):
    if n <= i * 1.08 < n+1:
        print(i)
        exit()
print(':(')

Solution (Python):
import math
N=int(input())
X1=math.ceil(N/1.08)
X2=math.floor(N/1.08)
if N==math.floor(X1*1.08):
    print(X1)
    exit(0)
if N==math.floor(X2*1.08):
    print(X2)
    exit(0)
print(":(")

Solution (Python):
n=int(input())
x=n/1.08
int_x=int(x)
if x-int_x==0:
    print(int_x)
else:
    if int(int_x*1.08)==n:
        print(int_x)
    elif int((int_x+1)*1.08)==n:
        print(int_x+1)
    else:
        print(':(')

Solution (Python):
from math import ceil

N = int(input())
X = ceil(N / 1.08)
print(X if int(X * 1.08) == N else ':(')

Solution (Python):

import sys
import math
from bisect import bisect_left
from bisect import bisect_right
import collections
import copy
import heapq
from collections import defaultdict
from heapq import heappop, heappush
import itertools
input = sys.stdin.readline






















def inputInt(): return int(input())
def inputMap(): return map(int, input().split())
def inputList(): return list(map(int, input().split()))

def main():
	N = inputInt()

	ans = -(-N // 1.08)
	ans2 = N / 1.08

	

	if ans2.is_integer():
		print(int(ans))
	else:
		tmp = ans2 - int(ans2)
		if tmp < 0.1:
			print(":(")
		else:
			print(int(ans))







if __name__ == "__main__":
	main()

Solution (Python):
n = int(input())
tax = 1.08
tmp = int(n/tax)
ret1 = int(tmp*tax)
ret2 = int((tmp+1)*tax)

if ret1 == n:
    print(tmp)
elif ret2 == n:
    print(tmp+1)
else:
    print(':(')

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

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

Solution (Python):
import sys

N = int(input())

for i in range(N+1):
    M = i*1.08
    if N == int(M):
        print(i)
        sys.exit()
print(":(")
sys.exit()

Solution (Python):

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

Solution (Python):
N = int(input())
Xmi = int(N / 1.08)
Xma = int((N+1) / 1.08)+1
ans = ":("
for i in range(Xmi,Xma+1):
  if int(i*1.08)==N:
    ans = i
print(ans)

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

if (N * 100) % 108 == 0:
    print(int(N / 1.08))
    exit()

M = int(N / 1.08) + 1
A = int(M * 1.08)

if A == N:
    print(int(M))
else:
    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 math

N = int(input())

X = math.ceil(N / 1.08)
converted = int(X * 1.08)
if N == converted:
    print(X)
else:
    print(':(')

Solution (Python):
n = int(input())
t = 1.08
ans = 0
for i in range(1,n+1):
    res = int(i*t)
    if res == n:
        ans = i
if ans == 0:
    print(':(')
else:
    print(ans)

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

Solution (Python):
import math
n = int(input())
base = math.floor(n/1.08)
for i in [-1, 0, 1]:
    moto = base+i
    if math.floor(moto*1.08) == n:
        print(moto)
        exit()
print(':(')

Solution (Python):
N = int(input())
X = N * 100 // 108
if N * 100 % 108 != 0:
    X += 1
if X * 108 // 100 == N:
    print(X)
else:
    print(':(')

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

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

X = int(N/1.08)

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

Solution (Python):
import math

N = int(input())

n = math.ceil(N/1.08)

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

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

Solution (Python):
n=int(input())
ans=-1
for i in range(n+100):
  if int(i*1.08)==n:
    ans=i
    break
print(":(" if ans==-1 else ans)

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

Solution (Python):
inf = float("inf")

n = int(input())

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

Solution (Python):
import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

def main():
    n = int(readline())
    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(":(")

if __name__ == "__main__":
    main()

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

flag = False
i = 0
for i in range(1,50001):
    if int(i * 1.08) == n:
        flag = True
        break


if flag:
    print(i)
else:
    print(":(")

Solution (Python):
N = int(input())
comp1 = N//1.08
comp2 = comp1+1
if int(comp1*1.08)==N:
  print(int(comp1))
  
elif int(comp2*1.08)==N:
  print(int(comp2))
  
else:
  print(':(')

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



def main():
    N = int(input())
    x = floor(N / 1.08)
    if floor(x * 1.08) == N:
        print(x)
    elif floor((x + 1) * 1.08) == N:
        print(x+1)
    elif floor((x - 1) * 1.08) == N:
        print(x - 1)
    else:
        print(":(")


if __name__ == "__main__":
    main()

Solution (Python):
n=int(input())
p=int(n/1.08)

x=int(p*1.08)

flag=0
if x==n:
  flag=1
  print(p)
if flag==0 and x<n:
  if int((p+1)*1.08)==n:
    print(p+1)
    flag=1
if flag==0 and x>n:
  if int((p-1)*1.08)==n:
    print(p-1)
if flag==0:
  print(":(")

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

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

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

for x in range(1,50000):
  if N==int(x*1.08):
    print(x)
    break
else:
  print(':(')

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

if n/1.08==int(n/1.08):
    print(int(n/1.08))

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

Solution (Python):
import math

n = int(input())
a = math.floor(n/1.08)
b = math.ceil(n/1.08)
if math.floor(a*1.08) == n:
  print(a)
elif math.floor(b*1.08) == n:
  print(b)
else:
  print(":(")

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

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

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

def hukano():
    print(":(")
def zeikomi(n):
    return n*1.08//1

N_min=N*9//10

k=N_min
while True:
    teika=int(zeikomi(k))
    if int(teika)==N:
        print(k)
        break
    elif teika<N:
        k=k+1
    else:
        hukano()
        break

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

nuki=A/1.08
kamo=int(nuki)+1
if int(kamo*1.08) == A:
    print(kamo)
elif int(int(nuki)*1.08) == A:
    print(int(nuki))
else:
    print(':(')

Solution (Python):
import math

p = int(input())


ans = math.ceil(p/(1.08))
con = math.floor(ans*1.08)

if p == con:
	print(ans)
else:
	print(":(")

Solution (Python):
N=int(input())
flg=-1

for i in range(N+1):
	if int(i*1.08)==N:
		flg=i
		break

if flg==-1:
	print(":(")
else:
	print(flg)

Solution (Python):
n = int(input())
if n % 27 == 13 or n % 27 == 26:
    print(':(')
elif n % 27 == 0:
    print(int(n / 1.08))
else:
    print(int(n / 1.08) + 1)

Solution (Python):
import math

n = int(input())

v = math.floor(math.ceil(n / 1.08) * 1.08)

if (v == n):
    print(math.ceil(n / 1.08))
else:
    print(":(")

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

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

Solution (Python):

import sys


def solve(N: int):
    X=int(N/1.08)
    for X in range(X, X+50000):
        if int(X*1.08)==N:
            print(X)
            return
        if X*1.08>N:
            print(":(")
            return



def main():
    def iterate_tokens():
        for line in sys.stdin:
            for word in line.split():
                yield word
    tokens = iterate_tokens()
    N = int(next(tokens))  
    solve(N)

if __name__ == '__main__':
    main()

Solution (Python):

N=int(input())
X=int(N/1.08)
if int((X+1)*1.08)==N:
  X +=1
print(X if int(X*1.08)==N else ':(')

Solution (Python):
k = [0] * 50001
for i in range(50001):
    k[i] = int(i*1.08)

n = int(input())
if n in k:
    for j in range(50001):
        if k[j] == n:
            print(j)
            break
else:
    print(':(')

Solution (Python):
N = int(input())
a = int(N / 1.08)
b = int(a * 1.08)
c = int((a + 1) * 1.08)

if N == b:
    print(a)
elif N == c:
    print(a + 1)
else:
    print(':(')

Solution (Python):
N = int(input())
for i in range(N+1):
    if i * 108 // 100 == N:
        print(i)
        exit()
print(":(")

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

Solution (Python):
import math

N = input()
N = int(N)

nuki = math.ceil(N*100/108)

X = math.floor(nuki * 1.08)

if N == X:
    print(nuki)
else:
    print(':(')

Solution (Python):
n=int(input())
memo=[]
for i in range(1,n+1):
  memo.append(int(i*1.08))

if n in memo:
  print(memo.index(n)+1)
else:
  print(":(")

Solution (Python):
from math import ceil
n = int(input())
m = ceil(n/1.08)

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

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

Solution (Python):

import sys

def _i(): return int(sys.stdin.readline().strip())

n = _i()

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

print(ans)

Solution (Python):
N = int(input())
Flag = False
count = 0
for i in range(50000):
    count = i
    i = i * 1.08
    i = int(i)
    if i == N:
        Flag = True
        break
    
if Flag == True:
    print(count)

else:
    print(":(")

Solution (Python):
n = int(input())
ans = int(n/1.08)
if n<=ans*1.08<n+1 and n<=(ans+1)*1.08<n+1:
  print(ans)
elif n<=ans*1.08<n+1 and (n>=(ans+1)*1.08 or (ans+1)*1.08>n+1):
  print(ans)
elif (n>=ans*1.08 or ans*1.08>n+1) and n<=(ans+1)*1.08<n+1:
  print(ans+1)             
else:
  print(":(")

Solution (Python):
n = int(input())
l = []
for i in range(1, 50401):
    l.append(int(i*1.08))
if n in l:
    if n/108*100 % 1 == 0:
        print(int(n/108*100))
    else:
        print(int(n/108*100)+1)
else:
    print(":(")

Solution (Python):

import sys
import math
args = sys.argv
if len(args) == 2:
  from IPython import embed
  em = True
else:
  em = False
input = sys.stdin.readline
N = float(input())
Nc = math.ceil(N / 1.08)
Nf = math.floor(N / 1.08)
if int(Nc * 1.08) == N:
  print(Nc)
elif int(Nf * 1.08) == N:
  print(Nf)
else:
  print(":(")

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

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

orgin=int(1+n//1.08)
orgintax= int(orgin*1.08)

if orgintax==n:
  print(orgin)
else:
  print(':(')

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

for i in range(1, n+100):
  ans = int(i*1.08)
  if ans == n:
    print(i)
    exit()
else:
  print(":(")

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

Solution (Python):
def f():
    n = int(input())
    a = n/1.08
    if a == int(a):
        print(int(a))
        return
    x = int(a) + 1
    if x >= ((n+1)/1.08):
        print(':(')
    else:
        print(x)

f()

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

if (n+1)/1.08-n/1.08>=1:
    print(int(n/1.08))
elif n/1.08==int(n/1.08) or int(n/1.08+1)<(n+1)/1.08:
    print(int((n+1)/1.08))
else:
    print(":(")

Solution (Python):
n=int(input())
for i in range(50001):
    if int(i*1.08)==n:
        print(i)
        break
    if i==50000:
        print(':(')
        break

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

Solution (Python):
import math
n=int(input())
if(n%1.08==0):
    print(int(n/1.08))
else:
    x=n/1.08
    n_low=int(math.floor(1.08*math.floor(x)))
    n_high=int(math.floor(1.08*math.ceil(x)))
    if(n==n_low):
        print(int(math.floor(x)))
    elif(n==n_high):
        print(int(math.ceil(x)))
    else:
        print(":(")

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

Solution (Python):
n = int(input())
r = 1.08
num = int(n/r)

small = int(num*r)
large = int((num + 1) *r)


if(n == small):
  print(num)
elif(n == large):
  print(num + 1)
else:
  print(":(")

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

Solution (Python):
def solve(zeikomi: int):
    for zeinuki in range(zeikomi + 1):
        if int(zeinuki * 1.08) == zeikomi:
            return zeinuki
    return None


zeikomi = int(input().strip())
zeinuki = solve(zeikomi)
if zeinuki is not None:
    print(zeinuki)
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())

X = int(N/1.08)






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

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

for i in range(N+1):
    x = i * 108 // 100
    if x == N:
        print(i)
        exit()

print(":(")

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):
N = int(input())

answer = N // 1.08

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