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 numpy as np

N = int(input())
X_low = N // 1.08
X_high = int(X_low + 1)

if np.floor(X_low * 1.08) == N:
    print(X_low)
elif np.floor(X_high * 1.08) == N:
    print(X_high)
else:
    print(':(')

Solution (Python):
import sys
n = int(input())
for i in range(1, 46300):
    if n*25/27 <= i < (n+1)*25/27:
        print(i)
        sys.exit()
print(":(")

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

if(n <= 12):
    print(n)
    sys.exit()

for y in range(n):
    if n == math.floor(y*1.08):
        print(y)
        found = True
        break
if (found == False):
    print(":(")

Solution (Python):

import math
N = int(input())

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

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

N_1 = round(N/1.08//1)
N_2 = N_1 + 1


if N_1*1.08//1 == N:
    print(N_1)

elif N_2 * 1.08//1 == N:
    print(N_2)

else:
    print(":(")

Solution (Python):
import math


def solve():
    N = int(input())
    if math.floor(math.ceil(N / 1.08) * 1.08) == N:
        print(math.ceil(N / 1.08))
    else:
        print(':(')


if __name__ == "__main__":
    solve()

Solution (Python):
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(':(')

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

Solution (Python):
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)))

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

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

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

ans = -1
for i in range(1, N + 1):
	if int(i * 1.08) == N:
		ans = i

if ans != -1:
	print(ans)
else:
	print(":(")

Solution (Python):
import math
num1 = int(input())
num2 = math.floor(num1 / 1.08)
num3 = math.ceil(num1 / 1.08)
end = False
if math.floor(math.floor(num1 / 1.08) * 1.08) == num1:
  print(math.floor(num1 / 1.08))
  end = True
elif math.floor(math.ceil(num1 / 1.08) * 1.08) == num1 and end == False:
  print(math.ceil(num1 / 1.08))
else:
  print(':(')

Solution (Python):
n=int(input())
m=int(n/1.08)
for i in range(-2,3):
    if int((m+i)*1.08)==n:
        print(m+i)
        exit()
print(":(")

Solution (Python):

import numpy as np
import sys
from collections import deque
from collections import defaultdict
import heapq
import collections
import itertools
import bisect
from scipy.special import comb
import copy
sys.setrecursionlimit(10**6)


def zz():
    return list(map(int, sys.stdin.readline().split()))


def z():
    return int(sys.stdin.readline())


def S():
    return sys.stdin.readline()[:-1]


def C(line):
    return [sys.stdin.readline() for _ in range(line)]


N = z()
min_ = int((N//1.08)-1)
for v in range(min_, min_+100):
    if (int(v * 1.08) == N):
        print(v)
        exit()

print(':(')

Solution (Python):
import math

N = int(input())

X = N/1.08

if (X % 1 == 0):
  print(int(X))
elif (math.floor(math.ceil(X) * 1.08) == N):
  print(math.ceil(X))
else:
  print(":(")

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

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

Solution (Python):
import math

N = int(input())

n = N / (1.08)

n0 = math.floor(n) - 1
n1 = math.floor(n)
n2 = math.ceil(n)

if int(n0 * 1.08) == N:
    print(n0)
elif int(n1 * 1.08) == N:
    print(n1)
elif int(n2 * 1.08) == N:
    print(n2)
else:
    print(":(")

Solution (Python):


import sys
input = sys.stdin.readline
sys.setrecursionlimit(10**7)
from collections import Counter, deque
from collections import defaultdict
from itertools import combinations, permutations, accumulate, groupby, product
from bisect import bisect_left,bisect_right
from heapq import heapify, heappop, heappush
from math import floor, ceil,pi,factorial
from operator import itemgetter
def I(): return int(input())
def MI(): return map(int, input().split())
def LI(): return list(map(int, input().split()))
def LI2(): return [int(input()) for i in range(n)]
def MXI(): return [[LI()]for i in range(n)]
def SI(): return input().rstrip()
def printns(x): print('\n'.join(x))
def printni(x): print('\n'.join(list(map(str,x))))
inf = 10**17
mod = 10**9 + 7
from decimal import *
n=I()
x=Decimal("1.08")
for i in range(1,100000):
    if int(i*x)==n:
        print(i)
        sys.exit()
print(":(")

Solution (Python):
import math
def main2():
    n = int(input())
    x = int(math.ceil(n / 1.08))
    
    if int(x*1.08) == n:
        print(x)
    else:
        print(":(")

if __name__ == "__main__":
    main2()

Solution (Python):
def main():
    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(":(")

if __name__ == "__main__":
    main()

Solution (Python):
n=int(input())
for i in range(1,50001):
    if i*108//100 == n:
        print(i)
        break
else:
    print(":(")

Solution (Python):
N = int(input())
tax_min = int(N*0.08/1.08)
tax_max = int((N+1)*0.08/1.08)
if tax_min != tax_max:
    print(":(")
else: print(N - tax_min)

Solution (Python):











def solve(n):
  for x in range(50000):
    if x * 108 // 100 == n:
      return x
  return ":("



def main():
  N = int(input())
  
  
  print(solve(N))
  return

if __name__ == '__main__':
  main()

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

Solution (Python):
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(':(')

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)
elif int((x+1) * 1.08) == n:
    print(x+1)
else:
    print(':(')

Solution (Python):
N = int(input())
flag = True
for i in range(100000):
  if int(i * 1.08) == N:
    print(i)
    flag = False
    break
if flag:
  print(":(")

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

for i in range(1, n + 1):
    x = int ( i * 1.08 )
    if x == n :
        print(i)
        found = True
        break

if not found:
    print(":(")

Solution (Python):
n = int(input())
for i in range(100000):
    if i * 108 // 100 == n:
        print(i)
        break
else:
    print(':(')

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

Solution (Python):
N = int(input())
n =int(N//1.1) 
while n<=N:
    if int(n*1.08)==N:
        print(n)
        exit()
    n+=1


print(":(")

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

Solution (Python):

import math
import sys
input = sys.stdin.readline  
N = int(input())
ans =":("
for i in range(1,50001):
    a =int( i *1.08 )
    if a==N:
        ans =i
        break
print(ans)

Solution (Python):
import math
N = int(input())
ans = math.ceil(100*N/108)
if math.floor(ans*1.08) == N:
    print(ans)
else:
    print(":(")

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

for x in range(1, 50001):
    if floor(x * 1.08) == N:
        print(x)
        break
else:
    print(":(")

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

res = -1
for x in range(1, n+1):
  if int(x * 1.08) == n:
    res = x

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

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

Solution (Python):
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()

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

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

Solution (Python):
import numpy

N = int(input())
X0 = N / 1.08
X1 = (N + 1) / 1.08

if numpy.ceil(X1) - numpy.ceil(X0) == 0:
    print(':(')
else:
    print(int(numpy.ceil(X0)))

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

for x in range(50001):
  y = int( x * 1.08 )
  if y == N:
    print(x)
    exit()
    
print(":(")

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

Solution (Python):

x = int(input())
for i in range(50000):
    if int(i * 1.08) == x:
        print(i)
        quit()
print(':(')

Solution (Python):
import math
N = int(input())
A = N/1.08 
B = (N+1)/1.08 

if math.ceil(N/1.08) < math.ceil((N+1)/1.08 ):
  print(math.ceil(N/1.08))
else:
  print(':(')

Solution (Python):
n =int(input())
b = False
for i in range(int(n//1.08-1), int(n//1.08+4),1):
    if n == int(i*1.08):
        b = True
        break

if b == True:
    print(i)
else:
    print(':(')

Solution (Python):
ni = lambda: int(input())
nm = lambda: map(int, input().split())
nl = lambda: list(map(int, input().split()))

from math import floor

n=ni()

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

Solution (Python):
n = int(input())
ans = int(n / 1.08)
if int(ans * 1.08) != n:
  ans = int(n / 1.08) + 1
  if (int(ans * 1.08)) != n:
    ans = ':('
print(ans)

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

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

resultA = N * 100 // 108
resultB = resultA + 1
valueA = resultA * 108 // 100
valueB = resultB * 108 // 100

if N == valueA:
  print(resultA)
elif N == valueB:
  print(resultB)
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())
for i in range(46298):
  if int(i*1.08)==n:
    print(i)
    break
else:
  print(":(")

Solution (Python):

import math

n = int(input())
x = {}

for i in range(1, 50001):
    x.setdefault(math.floor(i * 1.08), i)


try:
    print(x[n])
except:
    print(":(")

Solution (Python):
import math

N = int(input())

fl = math.floor(N / 1.08)
cl = math.ceil(N / 1.08)

if math.floor(fl * 1.08) == N:
    print(fl)
elif math.floor(cl * 1.08) == N:
    print(cl)
else:
    print(":(")

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

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

Solution (Python):
N = int(input())
a = int(N / 10)
x = 0

for i in range(a,N + 1):
    if N == int(i * 1.08):
        print(i)
        x += 1

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

Solution (Python):
from decimal import Decimal, ROUND_HALF_UP, ROUND_HALF_EVEN

import math

N = int(input())

X = N / 1.08


X = int(math.ceil(X))

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

Solution (Python):
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(':(')

Solution (Python):
def main():
    import sys
    def input(): return sys.stdin.readline().rstrip()
    n = int(input())
    for i in range(1,n+1):
        u = 108*i//100
        if u == n:
            print(i)
            break
        elif u > n:
            print(':(')
            break


if __name__ == '__main__':
    main()

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



import math
flag=':('
for x in range(1,n+1):
    price=math.floor(x*1.08)
    if math.floor(x*1.08) == n:
        flag=x
        break
print(flag)

Solution (Python):

n = int(input())

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

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

ans = (N * 100 + 99) // 108

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

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

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())

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 = float(input())

rate = 1.08
r = int(N / 1.08)
res = ":("
for i in range(r, r+3):
  if(int(i * rate) == N):
    res = str(i)
    break

print(res)

Solution (Python):
import math

N = int(input())

lower = N / 1.08

vl = math.ceil(lower)

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

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

for x in range(55000):
    if int(x*1.08)==n:
        print(x)
        exit()
print(":(")

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

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

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

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

Solution (Python):
import sys
n = int(input())
ans = n*100/108
for i in [int(ans), int(ans)+1]:
    if int(i*1.08) == n:
        print(i)
        sys.exit()
print(":(")

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

for v in range(int(n//1.08)+2):
    if int(v*1.08) == n:
        print(v)
        exit()
print(':(')

Solution (Python):
import math
N=int(input())
l=N*100/108
r=(N+1)*100/108
for i in range(math.ceil(l),math.ceil(r)):
    print(i);exit()
print(":(")

Solution (Python):
import sys
import time
import math
def inpl():
    return list(map(int, input().split()))
st = time.perf_counter()


N = int(input())
ls = [0] * 50505
for i in range(len(ls)):
	ls[i] = int(i * 1.08)
for i in range(N, 0, -1):
	if ls[i] == N:
		print(i)
		sys.exit()
print(':(')


ed = time.perf_counter()
print('time:', ed-st, file=sys.stderr)

Solution (Python):
N = int(input())
x = int(N/1.08)
for i in range(x, x+2):
    if N == int(i*1.08):
        print(i)
        break
else:
    print(":(")

Solution (Python):
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(":(")

Solution (Python):

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)

Solution (Python):
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(':(')

Solution (Python):
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(":(")

Solution (Python):
n = int(input())
for x in range(1, 50005):
    if x * 108//100 == n:
        print(x)
        exit()
else:
    print(':(')

Solution (Python):
N=int(input())
for i in range(1,500001):
    if int(i*1.08)==N:
        print(i)
        break
else:
      print(':(')

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

Solution (Python):

 

 
import sys
from fractions import gcd
import math
from math import ceil,floor
import collections
from collections import Counter
import itertools
import copy
 

 










 
N=int(input())

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

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

Solution (Python):
def resolve():
    paid = int(input())
    import math
    price = math.ceil(paid * 100 / 108)
    if price * 108 // 100 == paid:
        print(price)
    else:
        print(":(")


if __name__ == '__main__':
    resolve()

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

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

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

for X in range(1, N+1):
    if X*108//100==N:
        print(X)
        break
else:
    print(':(')

Solution (Python):
import math

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

if int(x*1.08) == N:
    print(x)
elif int(y*1.08) == N:
    print(y)
else:
    print(':(')

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

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

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

if ans!=-1:
  print(ans)
else:
  print(":(")

Solution (Python):

import math
def main():
    N = int(input())
    if N % 1.08 == 0:
        print(N/1.08)
    else:
        x = math.ceil(N/1.08)
        if x < (N+1)/1.08:
            print(x)
        else:
            print(':(')
    return
if __name__ == '__main__':
    main()

Solution (Python):
n = int(input())
for i in range(1, 50000):
  if i * 108 // 100 == n:
    print(i)
    exit()
print(':(')

Solution (Python):
n = int(input())
ans = 0
s = 0

while s < n:
    ans += 1
    s = int(ans*1.08)
    if s == n:
        print(ans)

if s != n:
    print(":(")

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

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

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

ans=N/1.08

ans=int(ans)
flag=True

while flag:
    if int(ans*1.08)<N:
        ans+=1
    elif int(ans*1.08)==N:
        break
    else:
        print(':(')
        flag=False
    
if flag:
    print(ans)

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

senter = N // 1.08

for i in range(1000):
    if int((senter-100+i) * 1.08) == N:
        print(int(senter-100+i))
        break
else:
    print(":(")

Solution (Python):
n = int(input())
c=0
for i in range(50000):
  if int(i * 1.08) == n:
    print(i)
    c = 1
    break
if c == 0:
  print(":(")

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

Solution (Python):

import sys
N = int(input())
x,y,k = 0,0,0

if N == 1:
    print(1)
    sys.exit()
elif N <= 12:
    print(N)
    sys.exit()
x = int(0.8*N)

for i in range(x,N):
    k = str(i*108)
    if int(k[0:-2]) == N:
        print(i)
        y +=1
        break

if y !=1:
    print(":(")

Solution (Python):
import math

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

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

Solution (Python):
import math

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

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

Solution (Python):

def my_index(l, x, default=False):
    if x in l:
        return int(l.index(x))+1
    else:
        return default

ans = []

num = int(input())

for i in range(1,50001):
    ans.append(int(i*1.08))

print(my_index(ans,num,":("))

Solution (Python):
n =int(input())
min = n//1.08
max = n//1.08+1
ans = 0
if int(min*1.08) == n:
    ans = min
if int(max*1.08) == n:
    ans = max
if ans != 0:
    print(int(ans))
else:
    print(":(")

Solution (Python):
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()

Solution (Python):
N = int(input())
t = int(N/1.08)
if(t*1.08 == N):
    print(t)
elif(int((t+1)*1.08) == N):
    print(t+1)
elif(int((t-1)*1.08) == N):
    print(t-1)
else:
    print(':(')

Solution (Python):
import math

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

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

Solution (Python):
def main():
    from decimal import Decimal
    x = Decimal(input())
    for i in range(60000):
        if int(Decimal(i)*Decimal('1.08'))==x:
            return i
    return ':('
print(main())

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

X = int(N/1.08)

for i in [-1, 0, 1]:
    X_ = int((X+i)*1.08)
    if(X_ == N):
        print(X+i)
        exit()

print(':(')

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

Solution (Python):
import math
n = int(input())
x, y = math.floor(n / 1.08), math.ceil(n / 1.08)
ans = ":("
if int(x * 1.08) == n:
    ans = x
elif int(y * 1.08) == n:
    ans = y
print(ans)

Solution (Python):
import math

N = int(input())
X = 0
a = 0
for i in range(50000):
  X = math.floor(1.08*i)
  if(X==N):
    print(i)
    a+=1
    break
if(a ==0):
  print(":(")

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

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

Solution (Python):
from math import ceil
n=int(input())
""" flag=True
xceil=ceil(n/1.08)
xfloor=int(n/1.08)
for i in range(xfloor,xceil+1):
    if int(i*1.08)==n:
        print(i)
        flag=False
        break
if flag:
    print(":(") """

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

Solution (Python):
from math import ceil
n=int(input())
flag=True
xceil=ceil(n/1.08)
xfloor=int(n/1.08)
for i in range(xfloor,xceil+1):
    if int(i*1.08)==n:
        print(i)
        flag=False
        break
if flag:
    print(":(")

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

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

for i in range(floor,ceil):
    print(i)
    break
else:
    print(":(")

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

Solution (Python):
N=int(input())
P,Q=108,100

A=(N*Q+P-1)//P
B=((N+1)*Q+P-1)//P-1

if A>B:
    print(":(")
else:
    print(A)

Solution (Python):
N = int(input())
 
for i in range(1, N + 1):
  if i + (i * 8) // 100 == N:
    print(i)
    break
else:
  print(":(")

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

dic = {}
for i in range(1,50000):
    dic[int(i * 1.08)] = i

if n in dic:
    print(dic[n])
else:
    print(':(')

Solution (Python):
import sys
input = sys.stdin.readline
sys.setrecursionlimit(10 ** 7)

n = int(input())

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

ans = bs(n, 0, lambda x: x * 1.08 >= n)
if int(ans * 1.08) == n:
    print(ans)
else:
    print(':(')

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

x_min = n * 100 / 108
x_max = (n + 1) * 100 / 108

print(math.ceil(x_min) if math.ceil(x_min) < x_max else ':(')

Solution (Python):

















import sys
def p(*_a):
  return
  _s=" ".join(map(str,_a))
  
  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)

Solution (Python):









N = int(input())

Xf = N / 1.08

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

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

min = math.floor(N / 1.08)
max = math.ceil(N/ 1.08)
flag = False
for i in range(min,max+1):
    ans = math.floor(i*1.08)
    if N == ans:
        X = i
        flag = True
        break
if(flag):
    print(X)
else:
    print(':(')

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

a = int(N/1.08)

for i in range(a-1, a+2):
    if int(i*1.08) == N:
        result = i
        break
else:
    result = ":("

print(result)

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

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

else:
    print(':(')

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

Solution (Python):
from math import ceil,floor

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

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

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

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

Solution (Python):
import math

N = int(input())

result = math.ceil(N / 1.08)

comfirm_result = int(result * 1.08)

if comfirm_result == N:
    print(result)
else:
    print(':(')

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

Solution (Python):
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(":(")

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

from decimal import Decimal

def calc(n):
    for i in range(60000):
        if int(Decimal(i) * Decimal('1.08')) == n:
            return i
    return ':('

print(calc(n))

Solution (Python):
def n_cand(x):
    return int(x*1.08)

n = int(input())

x = round(n / 1.08)
n_dash = n_cand(x)
n_dash_m = n_cand(x-1)
n_dash_p = n_cand(x+1)
if n_dash == n:
    print(x)
elif n_dash_m == n:
    print(x-1)
elif n_dash_p == n:
    print(x+1)
else:
    print(':(')

Solution (Python):
import sys

n = int(input())

for i in range(int(n / 1.08), int(n / 1.08) + 2):
    if int(i * 1.08) == n:
        print(i)
        sys.exit()
else:
    print(":(")

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

X_MAX = 50001
for x in range(X_MAX):
    if int(x * 1.08) == n:
        print(x)
        exit()
print(":(")

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

price = int(N / 1.08)

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

Solution (Python):
n = int(input())
import math
a = n*100/108
b = (n*100+100)/108
ans = math.ceil(a) if math.ceil(a) < b else ":("
print(ans)

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

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

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

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

Solution (Python):
def readinput():
    n=int(input())
    return n

def main(n):
    x7=int(n/1.07)+1
    x9=int(n/1.09)-1
    n100=n*100
    for x in range(max(1,x9),x7+1):
        xx=x*108//100
        
        if xx==n:
            print(x)
            break
    else:
        print(':(')

        

if __name__=='__main__':
    n=readinput()
    main(n)

Solution (Python):
def readinput():
    n=int(input())
    return n

def main(n):
    x7=int(n/1.07)
    x8=int(n/1.08)
    x9=int(n/1.09)
    n100=n*100
    for x in range(max(1,x9-1),x7+1+1):
        xx=x*108//100
        
        if xx==n:
            print(x)
            break
    else:
        print(':(')

        

if __name__=='__main__':
    n=readinput()
    main(n)

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

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

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

Solution (Python):
n = int(input())
x, mod = divmod(n, 1.08)
print(x if mod == 0 else
      int(x + 1) if int((x+1)*1.08) == n
      else ':(')

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

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

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

Solution (Python):
def main():
    N = int(input())
    for i in range(N + 1):
        ans = i * 108
        ans = ans // 100
        if ans == N:
            print(i)
            return
    print(':(')

main()

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

X = N / 1.08

X_down = int(X)
X_up = int(X) + 1

bool_down = int(X_down * 1.08) == N
bool_up = int(X_up * 1.08) == N

if bool_down:
    print(X_down)
elif bool_up:
    print(X_up)
else:
    print(":(")