Problem:
 Score : 100 points    Problem Statement Three poles stand evenly spaced along a line. Their heights are a , b and c meters, from left to right.
We will call the arrangement of the poles beautiful if the tops of the poles lie on the same line, that is, b-a = c-b .  Determine whether the arrangement of the poles is beautiful.      Constraints  1 \leq a,b,c \leq 100  a , b and c are integers.         Input Input is given from Standard Input in the following format:  a  b  c       Output Print YES if the arrangement of the poles is beautiful; print NO otherwise.        Sample Input 1 2 4 6      Sample Output 1 YES  Since 4-2 = 6-4 , this arrangement of poles is beautiful.       Sample Input 2 2 5 6      Sample Output 2 NO  Since 5-2 \neq 6-5 , this arrangement of poles is not beautiful.       Sample Input 3 3 2 1      Sample Output 3 YES  Since 1-2 = 2-3 , this arrangement of poles is beautiful.

Solution (Python):

a, b, c = map(int, input().split())



if b-a == c-b:
    print('YES')
else:
    print('NO')

Solution (Python):
def iroha():
    a, b, c = map(int, input().split())
    
    one = b - a
    two = c - b

    if one == two:
        print("YES")
    else:
        print("NO")



if __name__ == "__main__":
    iroha()

Solution (Python):
a,b,c=map(int, input().split())     
print("YES" if b-a==c-b else "NO")

Solution (Python):
A, B, C = [int(i) for i in input().split()]

if B - A == C - B:
  print('YES')
else:
  print('NO')

Solution (Python):
a,b,c = map(int,input().split())
print(['NO','YES'][b-a == c-b])

Solution (Python):
a,b,c = map(int, input().split())
if b-a==c-b:
  print("YES")
else:
  print("NO")

Solution (Python):
a,b,c=map(int,input().split())
print('YES' if b-a==c-b else 'NO')

Solution (Python):
a,b,c = map(int,input().split())

print('YES' if b-a == c-b else 'NO')

Solution (Python):
a, b, c = map(int,input().split())

if b - a == c - b:
  print("YES")
else:
  print("NO")

Solution (Python):


def main():
    a, b, c = map(int, input().split())
    print("YES" if b - a == c - b else "NO")


if __name__ == "__main__":
    main()

Solution (Python):
a,b,c = map(int,input().split())
if b-a == c-b:
    print('YES')
else:
    print('NO')

Solution (Python):
a = input().split()
if int(a[2])-int(a[1]) == int(a[1])-int(a[0]):
    print("YES")
else:
    print("NO")

Solution (Python):
a,b,c=map(int, input().split())
if (b-a)==(c-b):
  print('YES')
else:
    print('NO')

Solution (Python):
a,b,c = map(int,input().split())
print("YES" if b-a == c-b else "NO")

Solution (Python):
a, b, c = map(int, input().split())
if b-a == c-b:
    print("YES")
else:
    print("NO")

Solution (Python):
a,b,c=map(int,input().split())
if b-a==c-b: print("YES")
else: print("NO")

Solution (Python):
a,b,c=map(int,input().split())

if b-a==c-b:
    ans="YES"
else:
    ans="NO"

print(ans)

Solution (Python):
a,b,c=map(int,input().split())
if b-a==c-b:
  print("YES")
else:
  print("NO")

Solution (Python):
a,b,c = map(int, input().split())

d = b-a
e = c-b

if d == e:
    print('YES')
else:
    print('NO')

Solution (Python):
a, b, c = map(int, input().split())
if b-a==c-b:
    print('YES')
else:
    print('NO')

Solution (Python):
a, b, c = list(map(int, input().split()))
if b - a == c - b:
    print('YES')
else:
    print('NO')

Solution (Python):
a, b, c = map(int, input().split())

if b - a == c - b:
    print("YES")
else:
    print("NO")

Solution (Python):
a, b, c = map(int, input().split())
if b-a == c-b:
    print('YES')
else:
    print('NO')

Solution (Python):
a, b, c = map(int, input().split())
if b - a == c - b:
    print("YES")
else:
    print("NO")

Solution (Python):
a, b, c = map(int, input().split())

if b - a == c - b:
    print('YES')
else:
    print('NO')

Solution (Python):
a,b,c = map(int,input().split())
if b-a==c-b:
  print("YES")
else:
  print("NO")

Solution (Python):
a, b, c = map(int, input().split())
if b - a == c - b:
    print('YES')
else:
    print('NO')

Solution (Python):
a,b,c=map(int,input().split(" "))
print("YES") if b-a==c-b else print("NO")

Solution (Python):
a,b,c = map(int,input().split())
print("YES" if b-a == c-b else "NO")

Solution (Python):
a,b,c = map(int,input().split())
print('YES' if b-a == c-b else 'NO')

Solution (Python):
a, b, c = map(int,input().split())
if b - a == c - b:
    print('YES')
else:
    print('NO')

Solution (Python):
a, b, c = map(int, input().split())
if b - a == c - b:
  print("YES")
else:
  print("NO")

Solution (Python):


def read_int():
    return int(input().strip())


def read_ints():
    return list(map(int, input().strip().split(' ')))


def solve():
    a, b, c = read_ints()
    if b-a == c-b:
        return 'YES'
    return 'NO'


if __name__ == '__main__':
    print(solve())

Solution (Python):
a, b, c = map(int, input().split())
if b - a == c - b:
  print('YES')
else:
  print('NO')

Solution (Python):
a,b,c=map(int,input().split())
if b-a==c-b:
  print("YES")
else:
  print("NO")

Solution (Python):
a, b, c = map(int, input().split())
if b - a == c - b:
  print("YES")
else:
  print("NO")

Solution (Python):
a,b,c=map(int,input().split())
if b-a==c-b:
    print("YES")
else:
    print("NO")

Solution (Python):
a,b,c=map(int,input().split())
print("YNEOS"[2*b!=a+c::2])

Solution (Python):
a, b, c = input().split()

if int(b) - int(a) == int(c) - int(b):
    print("YES")
else:
    print("NO")

Solution (Python):
A, B, C = map(int, input().split())
if A + C == B * 2:
    print('YES')
else:
    print('NO')

Solution (Python):
a,b,c=map(int,input().split())
if a-b==b-c:print('YES')
else:print('NO')

Solution (Python):
def main():
    a, b, c = map(int, input().split())

    if b - a == c - b:
        print("YES")
    else:
        print("NO")


if __name__ == "__main__":
    main()

Solution (Python):

def main():
    a, b, c = map(int, input().split())

    if b-a == c-b:
        print('YES')
    else:
        print('NO')
  
        
if __name__ == '__main__':
    main()

Solution (Python):
def main():
    t = list(map(int, input().split()))
    if t[1] - t[0] == t[2] - t[1]:
        print('YES')
    else:
        print('NO')

if __name__ == '__main__':
    main()

Solution (Python):

a,b,c=map(int,input().split())
if b-a==c-b:
    print('YES')
else:
    print('NO')

Solution (Python):
a,b,c = map(int, input().split())
print('YES' if b-a == c-b else 'NO')

Solution (Python):
a, b, c= map(int, input().split())
if b-a==c-b:
    print("YES")
else:
    print("NO")

Solution (Python):
a, b, c = map(int, input().split())
if b - a == c - b:
  print('YES')
else:
  print('NO')

Solution (Python):

a, b, c = map(int, input().split())
if (1 <= a & a <= 100) & (1 <= b & b <= 100) & (1 <= c & c <= 100):
    d_ab = b - a
    d_bc = c - b
    if d_ab == d_bc:
        print('YES')
    else:
        print('NO')

Solution (Python):
import sys

readline = sys.stdin.readline
MOD = 10 ** 9 + 7
INF = float('INF')
sys.setrecursionlimit(10 ** 5)


def main():
    a, b, c = map(int, readline().split())

    if b - a == c - b:
        print("YES")
    else:
        print("NO")


if __name__ == '__main__':
    main()

Solution (Python):
a, b, c = map(int, input().split())
if b-a == c-b:
  print("YES")
else:
  print("NO")

Solution (Python):
a, b, c = map(int, input().split())

ans = 'NO'

if b - a == c - b:
    ans = 'YES'
elif a - b == b - c:
    ans = 'YES'

print(ans)

Solution (Python):
a,b,c = map(int,input().split())
print("YES" if b-a == c-b else "NO")

Solution (Python):
a, b, c = map(int,input().split())
print('YES') if b - a == c - b else print('NO')

Solution (Python):
a, b, c = map(int, input().split())
print(("NO", "YES")[b - a == c - b])

Solution (Python):
a, b, c = map(int, input().split())
print('YES' if b-a == c-b else 'NO')

Solution (Python):
a,b,c=map(int,input().split())
print("YES" if b-a==c-b else "NO")

Solution (Python):



a, b, c = map(int, input().split())

result = 'NO'

if b - a == c - b:
    result = 'YES'
elif a - b == b - c:
    result = 'YES'

print(result)

Solution (Python):
a, b, c = map(int, input().split())

if b-a == c-b:
    print("YES")
else:
    print("NO")

Solution (Python):
a, b, c = map(int, input().split())

if b - a == c - b:
    print('YES')
else:
    print('NO')

Solution (Python):
a=list(map(int,input().split()))
 
if a[0]+a[2]==2*a[1]:
  print('YES')
 
else:
  print('NO')

Solution (Python):
a, b, c = map(int, input().split())
if b-a == c-b:
    print("YES")
else:
    print("NO")

Solution (Python):
a,b,c=map(int,input().split())
if b-a==c-b:
  print("YES")
else:
  print("NO")

Solution (Python):
a, b, c = map(int, input().split())

if b - a == c - b:
    print('YES')
else:
    print('NO')

Solution (Python):


a, b, c = map(int, input().split())

if b - a == c - b:
    print('YES')
else:
    print('NO')

Solution (Python):
a,b,c=map(int,input().split())
if (b-a)==(c-b):
  print('YES')
else:
  print('NO')

Solution (Python):
a, b, c = map(int, input().split())

if (b - a) == (c - b):
    print('YES')
else:
    print('NO')

Solution (Python):

a, b, c = map(int,input().split())


if b - a == c - b:
    print('YES')
else:
    print('NO')

Solution (Python):





a,b,c = map(int,input().split())

if b-a == c-b:
    print('YES')
else:
    print('NO')

Solution (Python):




a,b,c = map(int,input().split())

if b - a == c - b:
    print('YES')

else:
    print('NO')

Solution (Python):
a, b, c = map(int, input().split())

if b - a == c - b:
    print("YES")
else:
    print("NO")

Solution (Python):

a, b, c = map(int, input().split())


if b - a == c - b:
    print('YES')
else:
    print('NO')

Solution (Python):
a, b, c = map(int,input().split())

if b - a == c - b:
    print("YES")
else:
    print("NO")

Solution (Python):
a, b, c = map(int, input().split())

if b - a == c - b:
    print('YES')
else:
    print('NO')

Solution (Python):
a, b, c = map(int, input().split())

if b - a == c - b:
    print("YES")
else:
    print("NO")

Solution (Python):

a, b, c = map(int, input().split())


if b - a == c - b:
    print('YES')
else:
    print('NO')

Solution (Python):
l=list(map(int,input().split()))
if(l[1]-l[0]==l[2]-l[1]):
    print("YES")
else:
    print("NO")

Solution (Python):

a,b,c = map(int,input().split())


if b - a == c - b:
    print("YES")
else:
    print("NO")

Solution (Python):
a,b,c = map(int,input().split())
if b-a == c-b:
    print("YES")
else:
    print("NO")

Solution (Python):
a, b, c = map(int,input().split())

if b - a == c - b :
    print( "YES" )
else:
    print( "NO" )

Solution (Python):
a, b, c = map(int, input().split())

if b - a == c - b:
    print('YES')
else:
    print('NO')

Solution (Python):




a, b, c = map(int, input().split())


if (b - a) == (c - b):
    print("YES")
else:
    print("NO")

Solution (Python):
S_list = list(map(int,input().split()))
 
if  S_list[1] - S_list[0] == S_list[2] - S_list[1]:
    result = "YES"
else:
    result = "NO"
print(result)

Solution (Python):
a,b,c=map(int,input().split())

if b-a==c-b:
  print('YES')
else:
  print('NO')

Solution (Python):
a,b,c=map(int,input().split());print('YNEOS'[b-a!=c-b::2])

Solution (Python):


a, b, c = map(int, input().split())

if b - a == c - b:
    print('YES')
else:
    print('NO')

Solution (Python):








a, b, c = map(int, input().split())



if (b - a) == (c - b):
    print("YES")
else:
    print("NO")

Solution (Python):
a,b,c = map(int,input().split())
if b-a == c-b:
    print('YES')
else:
    print('NO')

Solution (Python):
a, b, c = map(int, input().split())
print('YES' if b - a == c - b else 'NO')

Solution (Python):
a, b, c = map(int, input().split())

if b - a == c - b:
    print('YES')
else:
    print('NO')

Solution (Python):
a, b, c = map(int, input().split())

if b - a == c - b:
    print("YES")
else:
    print("NO")

Solution (Python):
pole1, pole2, pole3 = map(int, input().split())
if pole2 - pole1 == pole3 - pole2:
  print('YES')
else:
  print('NO')

Solution (Python):
a, b, c = map(int, input().split())
print('YES' if c - b == b - a else 'NO')

Solution (Python):
a,b,c = map(int,input().split())
if b-a == c-b:
  print('YES')
else:
  print('NO')

Solution (Python):
a,b,c = map(int,input().split())

print("YES" if b-a == c-b else "NO" )

Solution (Python):
a,b,c=map(int,input().split())
print("YES") if b-a==c-b else print("NO")

Solution (Python):

a,b,c = map(int,input().split())

if  b - a == c - b:
    print("YES")
else:
    print("NO")

Solution (Python):
a, b, c = map(int, input().split())

if (b-a) == (c-b):
    print('YES')
else:
    print('NO')

Solution (Python):
a,b,c=map(int,input().split())
if a-b == b-c:
  print("YES")
else:
  print("NO")

Solution (Python):
def solve():
    a, b, c = map(int, input().split())
    if b-a == c-b:
        print("YES")
    else:
        print("NO")


if __name__ == "__main__":
    solve()

Solution (Python):
a,b,c=input().split()
a=int(a)
b=int(b)
c=int(c)
if (b-a)==(c-b):
  print("YES")
else:
  print("NO")

Solution (Python):

a, b, c = map(int, input().split())


if b-a == c-b:
    print('YES')
else:
    print('NO')

Solution (Python):









a, b, c = map(int, input().split(maxsplit=3))



pillar_ba = b - a

pillar_cb = c - b




if pillar_ba == pillar_cb:
    answer = "YES"
else:
    answer = "NO"


print(answer)

Solution (Python):
a, b, c = (int(x) for x in input().split())
if b - a == c - b:
    print('YES')
else:
    print('NO')

Solution (Python):
a,b,c = map(int, input().split())

if b-a==c-b:
    print("YES")
else:
    print("NO")

Solution (Python):
a, b, c = map(int, input().split())
if b - a == c - b:
    print('YES')
else:
    print('NO')

Solution (Python):
a, b, c = map(int, input(). split())

if b - a == c - b:
    print('YES')
else:
    print('NO')

Solution (Python):
a, b, c = map(int, input().split())

if b - a == c - b:
    print('YES')
else:
    print('NO')

Solution (Python):
import sys
input = sys.stdin.readline
a = list(map(int, input().split()))
if a[1] - a[0] == a[2] - a[1]: print("YES")
else: print("NO")

Solution (Python):
a, b, c = map(int, input().split())
if b - a == c - b:
    print("YES")
else:
    print("NO")

Solution (Python):
a,b,c=map(int,input().split())
ans="NO"
if 2*b==a+c:
    ans="YES"
print(ans)

Solution (Python):
a_poll, b_poll, c_poll = map(int, input().split())

if b_poll - a_poll == c_poll - b_poll:
    print('YES')
else:
    print('NO')

Solution (Python):
a, b, c = map(int, input().split())

if b - a == c - b:
    print('YES')
else:
    print('NO')

Solution (Python):
import sys, re
from math import ceil, floor, sqrt, pi, factorial, gcd
from copy import deepcopy
from collections import Counter, deque
from heapq import heapify, heappop, heappush
from itertools import accumulate, product, combinations, combinations_with_replacement
from bisect import bisect, bisect_left, bisect_right
from functools import reduce
from decimal import Decimal, getcontext

def i_input(): return int(input())
def i_map(): return map(int, input().split())
def i_list(): return list(i_map())
def i_row(N): return [i_input() for _ in range(N)]
def i_row_list(N): return [i_list() for _ in range(N)]
def s_input(): return input()
def s_map(): return input().split()
def s_list(): return list(s_map())
def s_row(N): return [s_input for _ in range(N)]
def s_row_str(N): return [s_list() for _ in range(N)]
def s_row_list(N): return [list(s_input()) for _ in range(N)]
def lcm(a, b): return a * b // gcd(a, b)
sys.setrecursionlimit(10 ** 6)
INF = float('inf')
MOD = 10 ** 9 + 7
num_list = []
str_list = []

def main():
    a, b, c = i_map()

    print('YES' if b-a == c-b else 'NO')

if __name__ == '__main__':
    main()

Solution (Python):

a, b, c = map(int, input().split())
if b - a == c - b:
    print('YES')
else:
    print('NO')

Solution (Python):
a,b,c =map(int,input().split())
if c-b ==b-a:
  print("YES")
else:
  print("NO")

Solution (Python):
a,b,c=map(int,input().split())
print('YES' if b-a==c-b else 'NO')

Solution (Python):
a,b,c = map(int,input().split())
if b-a == c-b:
  print("YES")
else:
  print("NO")

Solution (Python):
a, b, c = map(int, input().split())
if b - a == c - b:
  print("YES")
else:
  print("NO")

Solution (Python):
a, b, c = map(int, input().split())
if b - a == c - b:
    print("YES")
else:
    print("NO")

Solution (Python):
a, b, c = map(int, input().split())
if b-a == c-b:
  print('YES')
else:
  print('NO')

Solution (Python):
a, b, c = map(int, input().split())
print('YES' if b - a == c - b else 'NO')

Solution (Python):
a, b, c = input().split(' ')
a = int(a)
b = int(b)
c = int(c)
if b-a == c-b:
  print("YES")
else:
  print("NO")

Solution (Python):
a, b, c = map(int, input().split())
if b-a == c-b:
  print("YES")
else:
  print("NO")

Solution (Python):
a,b,c = map(int, input().split())
if b-a == c-b:
  print("YES")
else:
  print("NO")

Solution (Python):
import sys
def input(): return sys.stdin.readline().strip()

def main():
    a, b, c = map(int, input().split())
    if b - a == c - b:
        print("YES")
    else:
        print("NO")
    

if __name__ == "__main__":
    main()

Solution (Python):
a, b, c = map(int, input().split())
if b - a == c - b:
    print('YES')
else:
    print('NO')

Solution (Python):
a, b, c = map(int, input().split())
if b - a == c - b:
  print("YES")
else:
  print("NO")

Solution (Python):
a,b,c=(int(x) for x in input().split())
d = c - b
e = b - a
if d == e:
    print('YES')
else:
    print('NO')

Solution (Python):
a,b,c=map(int,input().split())
if 2*b==a+c:
  print('YES')
else:
  print('NO')

Solution (Python):
a,b,c = map(int,input().split())
if b-a == c-b: print('YES')
else: print('NO')

Solution (Python):
a,b,c=map(int,input().split())
if b-a == c-b:
    print("YES")
    
else:
    print("NO")

Solution (Python):
a,b,c=map(int,input().split())
if b-a == c-b:
  print("YES")
else:
  print("NO")

Solution (Python):
a,b,c=map(int,input().split())
print('YES'if b-a==c-b else'NO')

Solution (Python):
h=list(map(int,input().split()))
w=sorted(h)
if (w[1]-w[0])==(w[2]-w[1]):
  print('YES')
else:
  print('NO')

Solution (Python):
a,b,c = map(int,input().split())
if b-a==c-b:
    print('YES')
else:
    print('NO')

Solution (Python):
a,b,c = map(int, input().split())
if b-a == c-b:
    print('YES')
else:
    print('NO')

Solution (Python):
import sys

read = sys.stdin.read
readline = sys.stdin.buffer.readline
sys.setrecursionlimit(10 ** 8)
INF = float('inf')
MOD = 10 ** 9 + 7


def main():
    a, b, c = map(int, readline().split())
    if b-a==c-b:
        print('YES')
    else:
        print('NO')



if __name__ == '__main__':
    main()

Solution (Python):
a,b,c=map(int,input().split())
print(["NO","YES"][2*b==a+c])

Solution (Python):
a,b,c=map(int,input().split())
if b-a==c-b:print('YES')
else:print('NO')

Solution (Python):
a, b, c = map(int, input().split())

if b-a == c-b:
    print('YES')
else:
    print('NO')

Solution (Python):
a,b,c =map(int,input().split())
print(["YES","NO"][b-a != c-b])

Solution (Python):
a,b,c=map(int,input().split())
if b-a==c-b:
  print("YES")
else:
  print("NO")

Solution (Python):
a,b,c=map(int,input().split())
if (c-b)==(b-a):
  print("YES")
else:
  print("NO")

Solution (Python):








a,b,c = map(int, input().split())

if (b - a == c - b):
    print("YES")
else:
    print("NO")

Solution (Python):
a, b, c = map(int, input().split())
print('YES') if b - a  == c - b else print('NO')

Solution (Python):
a,b,c=map(int,input().split())
print(["NO","YES"][2*b-a-c==0])

Solution (Python):
a,b,c = map(int,input().split())
if b-a == c-b:
  print('YES')
else:
  print('NO')

Solution (Python):
a,b,c=map(int, input().split())
if b-a == c-b:
    print("YES")
else:
    print("NO")

Solution (Python):
a, b, c = map(int, input().split())

x = b-a
y = c-b

if x == y:
  ans = 'YES'
else:
  ans = 'NO'
  
print(ans)

Solution (Python):
a, b, c = map(int, input().split())
print('YES' if b-a == c-b else 'NO')

Solution (Python):
a, b, c = map(int,input().split())

print("YES" if b-a == c-b else "NO")

Solution (Python):
a, b, c = map(int, input().split())
if b - a == c - b:
    print('YES')
else:
    print('NO')

Solution (Python):
a,b,c = map(int,input().split())
print("YES" if b-a == c-b else "NO")

Solution (Python):
a,b,c=map(int,input().split())
if b-a==c-b:
    print("YES")
else:
    print("NO")

Solution (Python):
a,b,c=map(int,input().split())
if a-2*b+c==0:
    print("YES")
else:
    print("NO")

Solution (Python):
a, b, c = map(int, input().split())
if b-a == c-b:
    print('YES')
else:
    print('NO')

Solution (Python):
a,b,c=map(int,input().split())
if b-a==c-b:
    print('YES')
else:
    print('NO')

Solution (Python):
a,b,c=map(int,input().split())
print("YES" if b-a==c-b else "NO")

Solution (Python):
a, b, c = list(map(int, input().split()))
if b - c == a - b:
  my_result = 'YES'
else:
  my_result ='NO'
print(my_result)

Solution (Python):
a,b,c = (int(T) for T in input().split())
print(['NO','YES'][(c-b)==(b-a)])

Solution (Python):

















import sys, re
from collections import deque, defaultdict, Counter
from math import ceil, sqrt, hypot, factorial, pi, sin, cos, radians
from itertools import accumulate, permutations, combinations, product
from operator import itemgetter, mul
from copy import deepcopy
from string import ascii_lowercase, ascii_uppercase, digits
from bisect import bisect, bisect_left
from fractions import gcd
from heapq import heappush, heappop
from functools import reduce
import numpy as np
def input(): return sys.stdin.readline().strip()
def INT(): return int(input())
def MAP(): return map(int, input().split())
def LIST(): return list(map(int, input().split()))
def ZIP(n): return zip(*(MAP() for _ in range(n)))
sys.setrecursionlimit(10 ** 9)
INF = float('inf')
mod = 10 ** 9 + 7

a, b, c = MAP()
if (b - a) == (c - b):
    print("YES")
else:
    print("NO")

Solution (Python):
ary = list(map(lambda n: int(n), input().split(" ")))

print("NO") if 2 * ary[1] - ary[0] - ary[2] else print("YES")

Solution (Python):
a,b,c=map(int,input().split())
if b-a==c-b:
  print("YES")
else:
  print("NO")

Solution (Python):
a,b,c = map(int,input().split())

if(b-a) ==(c-b):
    print('YES') 
else:
    print('NO')

Solution (Python):
a,b,c=map(int,input().split())
if b-a==c-b:
  print("YES")
else:
  print("NO")

Solution (Python):
a, b, c = [int(x) for x in input().split()]
print("YES" if b - a == c - b else "NO")

Solution (Python):
A, B, C = map(int,input().split())

if 2*B == A+C:
    print("YES")
else:
    print("NO")

Solution (Python):
a, b, c = map(int, input().split())
if b-a == c-b:
    print("YES")
else:
    print("NO")

Solution (Python):
a,b,c = map(int,input().split())

if b-a == c-b:
    print('YES')
else:
    print('NO')

Solution (Python):
a,b,c = map(int,input().split())
if b-a == c-b:
	print("YES")
else:
	print("NO")

Solution (Python):
a,b,c=map(int,input().split())

if b - a == c - b:
    print('YES')
else:
    print('NO')

Solution (Python):
a, b, c = map(int, input().split())
if b - a == c - b:
    print('YES')
else:
    print('NO')

Solution (Python):
a,b,c=map(int,input().split())
print('YES' if b-a==c-b else 'NO')

Solution (Python):
a, b, c = map(int, input().split())
if b - a == c - b:
    print("YES")
else:
    print("NO")

Solution (Python):
def is_beautiful(a,b,c):
  return b-a==c-b

a,b,c=map(int,input().split())
if is_beautiful(a,b,c):
  print("YES")
else:
  print("NO")

Solution (Python):
a, b, c = map(int, input().split())

if (b - a) == (c - b):
  print('YES')
else:
  print('NO')

Solution (Python):
a,b,c=map(int,input().split())
print("YES" if b-a==c-b else "NO")

Solution (Python):
a, b, c = map(int, input().split())

if b - a == c - b:
  print('YES')
else:
  print('NO')

Solution (Python):
a,b,c=map(int,input().split())

if b-c==a-b:
  print('YES')
else:
  print('NO')

Solution (Python):
import sys

read = sys.stdin.read
readline = sys.stdin.readline
readlines = sys.stdin.readlines
sys.setrecursionlimit(10 ** 9)
INF = 1 << 60
MOD = 1000000007


def main():
    a, b, c = map(int, readline().split())

    if b - a == c - b:
        print('YES')
    else:
        print('NO')

    return


if __name__ == '__main__':
    main()

Solution (Python):
a, b, c = map(int, input().split())
if b-a == c-b:
    print("YES")
else:
    print("NO")

Solution (Python):
a, b, c = map(int, input().split())

if b-a == c-b:
    print('YES')
else:
    print('NO')

Solution (Python):
a,b,c=map(int,input().split())
print("YES" if (b-a)==(c-b) else "NO")

Solution (Python):
a , b, c     = map(int,input().split())
print('YES' if b-a == c-b else 'NO')

Solution (Python):
a = list(map(int, input().split()))
print("YES" if a[1] - a[0] == a[2] - a[1] else "NO")

Solution (Python):
a, b, c = map(int, input().split())
if b - a == c - b:
    print('YES')
else:
    print('NO')

Solution (Python):
a,b,c = map(int, input().split())
if b-a == c-b:
  print("YES")
else:
  print("NO")

Solution (Python):
A,B,C = map(int,input().rstrip().split(" "))
if B-A == C-B:print("YES")
else:print("NO")

Solution (Python):
a,b,c = map(int, input().split())

YN = lambda b: print('YES') if b else print('NO')
YN( b-a==c-b )

Solution (Python):
a,b,c = map(int, input().split())

print('YES' if b - a == c - b else 'NO')

Solution (Python):
a, b, c = map(int, input().split())
print("YES" if b - a == c - b else "NO")

Solution (Python):
a, b, c = map(int, input().split())
if b-a == c-b:
  print('YES')
else:
  print('NO')

Solution (Python):
a,b,c=map(int,input().split())
d = b-a
e = c-b
if d == e:
  print("YES")
else:
  print("NO")

Solution (Python):
a, b, c = map(int,input().split())
print("YES" if b-a == c-b else "NO")

Solution (Python):
a,b,c = map(int, input().split())

print("YES") if b-a == c-b else print("NO")

Solution (Python):
import sys
import math
import itertools
import bisect
from copy import copy
from collections import deque,Counter
from decimal import Decimal
def s(): return input()
def i(): return int(input())
def S(): return input().split()
def I(): return map(int,input().split())
def L(): return list(input().split())
def l(): return list(map(int,input().split()))
def lcm(a,b): return a*b//math.gcd(a,b)
sys.setrecursionlimit(10 ** 9)
INF = 10**9
mod = 10**9+7

a,b,c = I()
if b-a == c-b:
    print('YES')
else:
    print('NO')

Solution (Python):
a,b,c = map(int,input().split())
print(['NO','YES'][b-a==c-b])

Solution (Python):
a,b,c = map(int,input().split())
print('YES' if c-b == b-a else 'NO')

Solution (Python):
a,b,c=map(int,input().split())
if b-a==c-b:
    print("YES")
else:
    print("NO")

Solution (Python):
def solve():
    A, B, C = map(int, input().split())

    if B - A == C - B:
        return True

    return False


if __name__ == '__main__':
    res = solve()
    if res:
        print("YES")
    else:
        print("NO")

Solution (Python):
a,b,c=map(int,input().split())

if 2*b-a-c==0:
    print("YES")
else:
    print("NO")

Solution (Python):
a,b,c = (int(x) for x in input().split())
if b-a == c-b:
  print ('YES')
else:
  print ('NO')

Solution (Python):
a, b, c = map(int, input().split())

if b-a==c-b:
    print('YES')
else:
    print('NO')

Solution (Python):
a,b,c=map(int,input().split())
if b-a==c-b:
    print('YES')
else:
    print('NO')

Solution (Python):
a, b, c = map(int, input().split())
if b-a == c-b:
    print('YES')
else:
    print('NO')

Solution (Python):
a, b, c = map(int, input().split())
print('YES' if b-a == c-b else 'NO')

Solution (Python):
A, B, C = map(int, input().split())

print("YES" if B - A == C - B else "NO")

Solution (Python):
a, b, c = list(map(int, input().split()))

if (b-a) == (c-b):
    print("YES")
else:
    print("NO")

Solution (Python):
a,b,c = map(int,input().split())
if b - a == c - b:
    print("YES")
else:
    print("NO")

Solution (Python):
a, b, c = map(int, input().split())
print(['NO','YES'][b - a == c - b])

Solution (Python):
import sys
import math
import itertools
import collections
import heapq
import re
import numpy as np

rr = lambda: sys.stdin.readline().rstrip()
rs = lambda: sys.stdin.readline().split()
ri = lambda: int(sys.stdin.readline())
rm = lambda: map(int, sys.stdin.readline().split())
rl = lambda: list(map(int, sys.stdin.readline().split()))
inf = float('inf')
mod = 10**9 + 7

a, b, c = rm()
if b-a == c-b:
  print('YES')
else:
  print('NO')

Solution (Python):
a,b,c=map(int,input().split())
if b-a==c-b:
  print('YES')
else:
  print('NO')

Solution (Python):
a, b, c = map(int, input().split())

if b - a == c - b:
    print('YES')
else:
    print('NO')

Solution (Python):
A, B, C = map(int,input().split())
if B-A == C-B:
  print("YES")
else:
  print("NO")

Solution (Python):
a, b, c = map(int, input().split())

if b - a == c - b:
    print("YES")
else:
    print("NO")

Solution (Python):
a,b,c=map(int,input().split())
if b*2==a+c:
  print("YES")
else:
  print("NO")

Solution (Python):
a,b,c=list(map(int,input().split()))
if b - a == c - b:
  print("YES")
else:
  print("NO")

Solution (Python):
a,b,c = map(int, input().split())
if b-a == c-b:
    print("YES")
else:
    print("NO")

Solution (Python):
a,b,c=map(int,input().split())
if b-a==c-b:
    print("YES")
else:
    print("NO")

Solution (Python):
A, B, C = map(int, input().split())
print("YES" if B-A == C-B else "NO")

Solution (Python):
a,b,c = map(int,input().split())
print("YES" if b-a == c-b else "NO")

Solution (Python):
a, b, c = map(int, input().split())
if b - a == c - b:
    print('YES')
else:
    print('NO')

Solution (Python):

lst = input().split()

a = int(lst[0])
b = int(lst[1])
c = int(lst[2])


if b - a == c - b:
   print('YES')
else:
   print('NO')

Solution (Python):
import bisect,collections,copy,heapq,itertools,math,string
import sys
def S(): return sys.stdin.readline().rstrip()
def M(): return map(int,sys.stdin.readline().rstrip().split())
def I(): return int(sys.stdin.readline().rstrip())
def LI(): return list(map(int,sys.stdin.readline().rstrip().split()))
def LS(): return list(sys.stdin.readline().rstrip().split())
a, b, c = M()
x = b-a
y = c-b
if x == y:
    print('YES')
else:
    print('NO')

Solution (Python):
a,b,c=map(int, input().split())
if a-2*b+c==0:
  print("YES")
else:
  print("NO")

Solution (Python):
a,b,c=map(int,input().split())
print("YES" if b-a==c-b else "NO")

Solution (Python):
a, b, c = map(int, input().split())

if b-a == c-b:
  print('YES')
else:
  print('NO')

Solution (Python):
a,b,c=map(int,input().split())
print('YNEOS'[a+c!=b+b::2])

Solution (Python):
a,b,c=map(int,input().split())
print('YES' if (b-a)==(c-b) else 'NO')

Solution (Python):
a,b,c=map(int,input().split())
if b-a==c-b:
  print("YES")
else:
  print("NO")

Solution (Python):
a,b,c=map(int,input().split())
if b-a==c-b:
  print("YES")
else:
  print("NO")

Solution (Python):
i = [int(s) for s in input().split()]
A = i[1] - i[0]
Atwo = i[2] - i[1]
if A == Atwo:
    print("YES")
else:
    print("NO")

Solution (Python):
def main():
    a, b, c = map(int, input().split())
    if b - a == c - b:
        print('YES')
    else:
        print("NO")


if __name__ == "__main__":
    main()

Solution (Python):
a,b,c = map(int,input().split())


if b-a == c-b:
  print("YES")
else:
  print("NO")

Solution (Python):
def resolve():
    a,b,c  = map(int,input().split())
    print("YES" if b-a==c-b else "NO")
resolve()

Solution (Python):
a,b,c = map(int,input().split())
if b - a == c - b:
    print("YES")
else:
    print("NO")

Solution (Python):
from fractions import gcd
from collections import Counter, deque, defaultdict
from heapq import heappush, heappop, heappushpop, heapify, heapreplace, merge
from bisect import bisect_left, bisect_right, bisect, insort_left, insort_right, insort
from itertools import accumulate, product, permutations, combinations

def main():
    a, b, c = map(int, input().split())

    print('YES') if b - a == c - b else print('NO')

if __name__ == '__main__':
    main()

Solution (Python):
a , b , c  = map(int,input().split())
if b - a == c - b:
  print('YES')
else:
  print('NO')