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())
tmp1 = math.ceil(N / 1.08)
tmp2 = int(tmp1 * 1.08)

if N == tmp2:
    print(tmp1)
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):
import math

N = int(input())
n = N / 1.08

if int(math.ceil(n) * 1.08) == N: print(math.ceil(n))
else: print(':(')

Solution (Python):
import sys
from math import ceil, floor
def main():
    n = int(sys.stdin.readline().rstrip())
    x = ceil(n * 100 / 108) 
    if floor(x * 1.08) == n:
        print(x)
    else:
        print(':(')
if __name__ == '__main__':
    main()

Solution (Python):


import sys
import math
import collections
import itertools
from inspect import currentframe
INF = 10 ** 10
MOD = 10 ** 9 + 7
def input() : return sys.stdin.readline().strip()
def gcd(x, y) : return y if x % y == 0 else gcd(y, x % y)
def lcm(x, y) : return (x * y) // gcd(x, y)
def I() : return int(input())
def MI() : return map(int, input().split())
def LI() : return [int(x) for x in input().split()]
def RI(N) : return [int(input()) for _ in range(N)]
def LRI(N) : return [[int(x) for x in input().split()] for _ in range(N)]
def chkprint(*args) : names = {id(v):k for k,v in currentframe().f_back.f_locals.items()}; print(', '.join(names.get(id(arg),'???')+' = '+repr(arg) for arg in args))

N = I()

for i in range(1, 500100):
    if int(i * 1.08) == N:
        print(i)
        break
else:
    print(":(")

Solution (Python):
n = int(input())
x = 0
while True:
    if x > n:
        res = ':('
        break

    if int(x*1.08)==n:
        res = x
        break

    x += 1

print(res)

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


x = math.ceil(n/1.08)

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

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

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

m = int(n // 1.08)

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

Solution (Python):
N=input()

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

Solution (Python):
import sys
import math

sys.setrecursionlimit(10**7)
INF = 10 ** 18
MOD = 10 ** 9 + 7
def LI(): return list(map(int, sys.stdin.readline().split()))
def II(): return int(sys.stdin.readline())
def LS(): return list(map(list, sys.stdin.readline().split()))
def S(): return list(sys.stdin.readline())[:-1]

def main():
    n = II()
    ans = int(math.floor(n / 1.08))

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

if __name__ == '__main__':
    main()

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):

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

    for i in range(int(N/1.1),N+1):
        if int(i*1.08)==N:
            print(i)
            return 0
    else:
        print(':(')



if __name__ == "__main__":
    resolve()

Solution (Python):

n = int(input())
for x in range(1, 2 * n):
    if x * 108 // 100 == n:
        print(x)
        break
else:
    print(':(')

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

x = n / 1.08

if x == x // 1:
    print(int(x))

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

Solution (Python):
n = int(input())
import numpy as np
X = np.ceil(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(":(")

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

ans = ":("
for i in range(1, 50001):
    tmp = i * 1.08
    tmp = int(tmp)
    if n == tmp:
        ans = i
        break

print(ans)

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

Solution (Python):
from math import floor

n = int(input())

bl = False
for x in range(1, 60000):
    if floor(x * 1.08) == n:
        bl = True
        break

print(x if bl else ":(")

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 math
n = int(input())

a = math.floor(n/1.08)
b = math.floor(n/1.08) + 1

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

Solution (Python):
n=int(input())
res=0
for i in range(1,50000):
    if int(i*1.08)==n:
        res=i
        break
print(res if res>0 else ':(')

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

i = 1
while True:
    if int(i * 1.08) == N:
        break
    if i > N:
        i = 0
        break
    i += 1

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

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

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

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

Solution (Python):
N  = int(input())
x = int(N*100/108)
s = True
for i in range(max(0,x-13),x+13):
    if int(i*1.08)==N:
        print(i)
        s =False
        break
if s:
    print(":(")

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

def solve():
    for i in range(1,n+1):
        if i * 1.08 >= n and i * 1.08 < n + 1:
            return i
    return ":("

print(solve())

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

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

Solution (Python):
import numpy as np
def main():
    N = int(input())
    ans = 0
    for x in range(50000):
        x += 1
        if np.floor(x * 1.08) == N:
            ans = x
            break
        if x == 50000 and ans == 0:
            ans = ":("
    
    print(ans)

if __name__ == '__main__':
    main()

Solution (Python):
import math
N = int(input())
ret = ':('
for i in range(1,50000+1):
    if math.floor(i*1.08) == N:
        ret = i
        break
print(ret)

Solution (Python):
N = int(input())
x1 = N//1.08
x2 = x1 + 1
if int(x1*1.08) == N:
    print(int(x1))
elif int(x2*1.08) == N:
    print(int(x2))
else:
    print(':(')

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

Solution (Python):
from sys import stdout
printn = lambda x: stdout.write(x)
inn = lambda : int(input())
inl   = lambda: list(map(int, input().split()))
inm   = lambda:      map(int, input().split())
DBG = True 
BIG = 999999999
R = 10**9 + 7

def ddprint(x):
  if DBG:
    print(x)

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

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

    ans = ":("
    for x in range(50000):
        tmp = x * 1.08
        tmp = math.floor(tmp)
        if tmp == N:
            ans = x 
            break
    
    print(ans)

if __name__ == '__main__':
    solve()

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

ans = 0
for i in range(n+1):
    if int(i*1.08)==n:
        ans = i
        break
if ans!=0:
    print(ans) 
else:
    print(':(')

Solution (Python):
import sys
import math

sys.setrecursionlimit(4100000)


def inputs(num_of_input):
    ins = [input() for i in range(num_of_input)]
    return ins


def solve(inputs):
    in_tax = int(inputs[0])
    not_tax = in_tax / 1.08
    kirisute = math.floor(not_tax)

    ks = [kirisute - 2, kirisute - 1, kirisute, kirisute + 1, kirisute + 2]
    for k in ks:
        c = math.floor(k * 1.08)
        if c == in_tax:
            return k
    return ':('


def string_to_int(string):
    return list(map(lambda x: int(x), string.split()))


if __name__ == "__main__":
    ret = solve(inputs(1))
    print(ret)

Solution (Python):
n=int(input())
if (n+1)%27==0 or (n+14)%27==0:
  print(":(")
else:
  print(int(n//1.08+1))

Solution (Python):
N=int(input())
for i in range(50000):
  if int(i*1.08)==N:
    print(i)
    exit(0)
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):
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
x = int(input())
a = int(x / 1.08)

for n in [a, a+1]:
    if (int(n * 1.08) == x):
        print(n)
        sys.exit()

print(':(')

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

for i in range(n+1):
  if math.floor(i*1.08) == n:
    print(i)
    sys.exit(0)
    

print(':(')

Solution (Python):
import math
n=int(input())
flg=0
for i in range(60000):
  if math.floor(i*1.08)==n:
    print(i)
    flg=1
    break
if flg==0:
  print(":(")

Solution (Python):
from math import floor, ceil
n = int(input())
x = floor(n / 1.08)
for i in range(-1,2):
    if floor((x+i) * 1.08) == n:
        print(x+i)
        break
else:
    print(':(')

Solution (Python):

"""
AtCoder A
"""

import sys, math, random
import numpy as np








inf = 10**20
eps = 1.0 / 10**10
mod = 10**9+7
dd = [(-1,0),(0,1),(1,0),(0,-1)]
ddn = [(-1,0),(-1,1),(0,1),(1,1),(1,0),(1,-1),(0,-1),(-1,-1)]

def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(): return [list(map(int, l.split())) for l in sys.stdin.readlines()]
def LI_(): return [int(x)-1 for x in sys.stdin.readline().split()]
def LF(): return [float(x) for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def I(): return int(sys.stdin.readline())
def F(): return float(sys.stdin.readline())
def S(): return input()


def main():
    X=I()
    
    Y=int(math.ceil(X/1.08))
    if X==math.floor(Y*1.08):
        print(Y)
    else:
        print(":(")
        
    

if __name__ == "__main__":
    main()

Solution (Python):
from math import ceil
n=int(input())
m=ceil(n/1.08)
M=int((n+1)/1.08)
if ((n+1)*100)%108==0:
  M-=1
if not m<=M:
  print(":(")
else:
  print(m)

Solution (Python):
N = int(input())
flag = 0
ans = 0
for i in range(1,50001):
    n = int(i*1.08)
    if N == n:
        ans = i
if ans == 0:
    print(":(")
else:
    print(ans)

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

Solution (Python):
import math

n = int(input())
ans = ":("
for i in range(1,n+1):
    if math.floor(i*1.08)==n:
        ans = i
        break

print(ans)

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

for i in range(1, N+1):
    tmp = (i * 1.08) // 1
    if tmp == N:
        ans = i
        break
    elif tmp > N:
        ans = ':('
        break
print(ans)

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

Solution (Python):
import sys
def input():
    return sys.stdin.readline()[:-1]
inf=float("inf")
n=int(input())
m=int(n/1.08)
if int(m*1.08)==n:
    print(m)
elif int((m+1)*1.08)==n:
    print(m+1)
else:
    print(":(")

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

X = N / 1.08
a = math.floor(X)
b = math.ceil(X)

if math.floor(a * 1.08) == N:
    print(a)
elif math.floor(b * 1.08) == N:
    print(b)
else:
    print(":(")

Solution (Python):
import sys
sys.setrecursionlimit(10**9)
import math

X = int(input())
def f(N):
    ret = int(math.floor(N*1.08))
    return ret

r = 5*10**4+1
l = 0
while (r-l)>1:
    mid = (r+l)//2
    ret = f(mid)
    if ret > X:
        r = mid
    elif ret == X:
        print(mid)
        exit()
    else:
        l = mid

print(":(")

Solution (Python):
n = int(input())
s = ":("
for i in range(50000):
    m = int(i*1.08)
    if (m == n):
        s = str(i)

print(s)

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

for i in range(50000):
    if i * 108 //100 == N:
        print(i)
        exit(0)
print(':(')

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

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


    


if __name__ == '__main__':
    main()

Solution (Python):
import math
N=int(input())
t=True
for i in range(1,50001):
    if math.floor(i*1.08)==N:
        print(i)
        t=False
        break

if t:
    print(":(")

Solution (Python):
import math

n = int(input())
ans = 0

for i in range(1,50001):
    nn = math.floor(i * 1.08)
    if nn == n:
        ans = i
        break

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

Solution (Python):
import math

N = int(input())

x = 1
while x <= 50000:
    if math.floor(x*1.08) == N:
        print(x)
        break
    x += 1
else:
    print(":(")

Solution (Python):

import sys, math


def solve(N: int):
    M = N / 1.08
    K = (N+1) / 1.08
    for i in range(N+1):
        if M <= i < K:
            print(i)
            return
    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())

def solve(N):
    for i in range(N + 1):
        if int(i * 1.08) == N:
            return i
    return ":("
print(solve(N))

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

Solution (Python):
n=int(input())
for i in range(int(n**0.5),50001):
    a=i*1.08
    if int(a)==n:
        print(i)
        exit()
print(":(")

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

def nibu(l,r):
    if l > r:
        return ':('
    c = (l+r)//2
    if (c*1.08)//1 == N:
        return c
    if (c*1.08)//1 < N:
        return nibu(c+1,r)
    elif (c*1.08)//1 > N:
        return nibu(l,c-1)

print(nibu(0,100000))

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

x = int((N + 1) / 1.08)
y = int(x * 1.08)

if N == y:
    print(x)
else:
    print(":(")

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

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())

X = N // 1.08
Y = X + 1

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

Solution (Python):

from collections import deque
import sys
sys.setrecursionlimit(10**6)
write = sys.stdout.write
dbg = lambda *something : print(*something) if DEBUG else 0
DEBUG = True

def index(a,b):
    return str(min(a,b)) + "," +  str(max(a, b))

def main(given = sys.stdin.readline):
    input = lambda : given().rstrip()
    LMIIS = lambda : list(map(int,input().split()))
    II = lambda : int(input())
    XLMIIS = lambda x : [LMIIS() for _ in range(x)]


    n = II()

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

    print(":(")



if __name__ == '__main__':
    main()

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

n=int(N/1.08)

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

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

ans = math.floor(N / 1.08)

while True:
    if math.floor(ans * 1.08) > N:
        print(':(')
        exit()
    if math.floor(ans * 1.08) == N:
        print(ans)
        exit()
    else:
        ans += 1

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

ans1 = math.floor(n/1.08)

if math.floor(ans1 * 1.08)== n:
    print(ans1)
elif math.floor((ans1+1) * 1.08)== n:
    print(ans1+1)
else:
    print(':(')

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

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

ans = (N*100 + 107) // 108

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

Solution (Python):
import sys
input = sys.stdin.readline
N = int(input())
for x in range(1, 50001):
  if int(x * 1.08) == N:
    print(x)
    exit(0)
print(":(")

Solution (Python):
import sys


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

    tax_rate = 1.08

    price = paid / tax_rate
    price = int(price + 0.9)

    if paid == int(price * tax_rate):
        print(price)
    else:
        print(':(')


if __name__ == '__main__':
    main()

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

for n in range(100000):
    ans = int(n * 1.08)
    if ans == N:
        print(n)
        break
else:
    print(':(')

Solution (Python):
n=int(input())
a=n//1.08
a+=(n%1.08!=0)
if int(a*1.08)==n:
  print(int(a))
else:
  print(':(')

Solution (Python):
def examB():
    N = I()
    max_N = 50001
    origin = [None]*int(max_N*1.08+10)
    for i in range(max_N):
        origin[int(i*1.08)] = i
    if origin[N]:
        ans = origin[N]
    else:
        ans = ":("
    print(ans)
    return

def examC():
    return

def examD():
    return
def examE():
    return

def examF():
    return

import sys,copy,bisect,itertools,math
from heapq import heappop,heappush,heapify
from collections import Counter,defaultdict,deque
def I(): return int(sys.stdin.readline())
def LI(): return list(map(int,sys.stdin.readline().split()))
def LS(): return sys.stdin.readline().split()
def SI(): return sys.stdin.readline().strip()
mod = 10**9 + 7
inf = float('inf')

examB()

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

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

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

ok = False
ans = 0
for i in range(1,50001):
    if int(i*1.08) == N:
        ans = i
        ok = True
if ok:
    print(ans)
else:
    print(":(")

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

Solution (Python):
N = int(input())
num = int(N/1.08)
num2 = num+1
if int(num*1.08)==N:
  print(num)
elif int(num2*1.08)==N:
  print(num2)
else:
  print(":(")

Solution (Python):
n=int(input())
ans=0
check=0
for i in range(1,50001):
    ans=int(i*1.08)
    if ans==n:
        check=1
        break
if check==1:
    print(i)
else:
    print(":(")

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

X = N//1.08
for n in range(10):
    X += n
    if int(X*1.08) == N:
        print(int(X))
        exit(0)
print(":(")

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

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

X = int(X_high - 0.001)

if X_low <= X < X_high:
    print(X)
else:
    print(":(")

Solution (Python):
import math
n = int(input())
x = math.ceil(n/1.08)
if (n+1)/1.08  > x:
  print(x)
else:
  print(":(")

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

X = int(N / 1.08)

flag = False
for i in range(10):
    if int((X + i) * 1.08) == N:
        print(X+i)
        flag = True
        break
if flag == False:
    print(':(')

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


def main():
    N = int(input())
    for x in range(50000+1):
        if int(x*1.08) == N:
            print(x)
            return
    print(":(")


if __name__ == '__main__':
    main()

Solution (Python):

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

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

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

for i in range(n+10):
    if floor(i * 1.08) == n:
        print(i)
        break
else: print(":(")

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

v = int(N / 1.08)
if int(v * 1.08) == N:
    print(v)
    sys.exit()
if int((v + 1) * 1.08) == N:
    print(v + 1)
    sys.exit()
print(':(')

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

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

Solution (Python):
N = int(input())
X = int(N/1.08)
flag=0
while True:   
    if int(X*1.08)==N:
        flag=1
        break
    elif int(X*1.08)>N:
        break
    X += 1
if flag==1:
    print(X)
else:
    print(":(")

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


def main():
    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 + 2) * 1.08):
        print(x + 2)
    elif N == int((x - 1) * 1.08):
        print(x - 1)
    elif N == int((x - 2) * 1.08):
        print(x - 2)
    else:
        print(":(")



if __name__ == '__main__':
    main()

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

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

for i in range (1,50000+1):
  if int(i * 1.08) == N:
    print(i)
    sys.exit()
print(":(")

Solution (Python):
import numpy as np
n=int(input())
mi=n/1.08
ma=(n+1)/1.08
x=np.ceil(mi)
if x<ma:
    print(int(x))
else:
    print(":(")

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

X = N / 1.08
if int(X) * 108 // 100 == N:
  print(int(X))
elif int(X + 1) * 108 // 100 == N:
  print(int(X + 1))
else:
  print(':(')

Solution (Python):
n = int(input())
x = [int(i*1.08) for i in range(1, 50001)]
try:
    print(x.index(n)+1)
except:
    print(":(")

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

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

N = int(input())

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

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

    for i in range(1,n+1):
        l=int(i*1.08)
        if l == n:
            print(i)
            return
    print(':(')
if __name__=='__main__':
    main()

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

exit(0)

Solution (Python):
import math
n = int(input())
fl = False
for i in range(5*10**4+1):
  k = math.floor(i*1.08)
  if k == n:
    print(i)
    fl = True
if not fl:
  print(":(")

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

Solution (Python):
import math

x = int(input())

y = math.ceil(x / 1.08)

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

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

X = N // 1.08

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

Solution (Python):
import math


def main():
    n = int(input())
    ans = -1;
    for i in range(n + 1):
        if int(math.floor(1.08 * i)) == n:
            ans = i
            break
    if ans == -1:
        print(':(')
    else:
        print(ans)

if __name__ == "__main__":
    main()

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

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

Solution (Python):
import sys
input=sys.stdin.readline
n=int(input())
import math
for i in range(n+1):
    x=math.floor(i*1.08)
    if n==x:
        print(i)
        sys.exit()
print(':(')

Solution (Python):
a=int(input())
s=a*25//27
for i in range(min(0,s-100),s+100):
  if i*27//25==a:print(i);exit()
else:print(":(")

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


temp = math.ceil(ans) * 1.08
if n == math.floor(temp):
    print(math.ceil(ans))
else:
    print(':(')

Solution (Python):

import sys
input = sys.stdin.buffer.readline


from collections import defaultdict


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


def main():
	N = int(input())
	X = int(N / 1.08 // 1)
	
	if int(X * 1.08 // 1) == N:
		print(X)
		return

	if int((X - 1) * 1.08 // 1) == N:
		print(X - 1)
		return

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

	print(":(")


if __name__ == '__main__':
	main()

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

Solution (Python):
import sys; readline = sys.stdin.readline
from collections import deque

k = ':('
R = 1.08
N = int(readline())


for i in range(N + 1):
    if int(R * i) == N:
        print(i)
        exit(0)

print(k)

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

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

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

r = 1.08

l = [int(n * r)for n in range(1,50000)]

if N in l:
  print(l.index(N)+1)
else:
  print(':(')

Solution (Python):

N = int(input())
tax = 1.08

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

Solution (Python):
paid = int(input())
for price in range(1, paid + 1):
    if int(price * 1.08) == paid:
        print(price)
        exit()
print(':(')

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

for x in range(1, 50001):
    if int(x * 1.08) == N:
        print (x)
        exit()

print (':(')

Solution (Python):
import math
n=int(input())
x=math.ceil(n*(100/108))
if math.floor(x*1.08)==n:
    print(x)
else:
    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())
for i in range(500001):
    if int(i*1.08)==n:
        print(i)
        break
else:
    print(':(')

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

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

Solution (Python):
n = int(input())
m = n + 0.99
l = int(m/1.08)
if int(l * 1.08) == n:
  print(l)
else:
  
  print(':(')

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

a=int(n//1.08)

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

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

X = N / 1.08

x1 = int(X)
x2 = int(X + 0.999999999)

if int(x1 * 1.08) == N:
    print(x1)
elif int(x2 * 1.08) == N:
    print(x2)
else:
    print(':(')

Solution (Python):
N = int(input())
for i in range(50001):
  if int(i * 1.08) == N:
    print(i)
    raise SystemExit
print(':(')

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

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

ans = N // 1.08

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

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

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

Solution (Python):
def main():
    n = int(input())
    ans = ":("
    for i in range(n+1):
        if int(i * 1.08) == n:
            ans = i
            break
    print(ans)
        
if __name__ == '__main__':
    main()

Solution (Python):

n = int(input())
a = int(n/1.08)


b = int(1.08 * a)
if b == n:
	print(a)
else:
	a += 1
	b = int(1.08 * a)
	if b == n:
		print(a)
	else:
		a += 1
		b = int(1.08 * a)
		if b == n:
			print(a)
		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())

num_dict={}
for x in range(1,100000+1):
  v = math.floor(x*1.08)
  num_dict[v]=x

if n in num_dict:
  ret=num_dict[n]
else:
  ret=":("
  
print(ret)

Solution (Python):
import math

n = input()
for i in range(1, 1000001):
    if math.floor(i * 1.08) == n:
        print i
        exit(0)
print ':('

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