
# slower version:

s = input()
for i in range(len(s)):
  if i%2 == 0:
    print(s[i], end = '')


# optimized version of the same code:

s = input()
ans = ''
for i in range(len(s)):
  if i % 2 == 0:
    ans += s[i]
print(ans)



# slower version:

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

c = 0



for i in range(a,b+1):

  new = list(reversed(list(str(i))))

  if new == list(str(i)):

    c += 1

    

    

print(c)

# optimized version of the same code:

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

c = 0



for i in range(a,b+1):

  if list(str(i)) == list(str(i))[::-1]:

    c += 1

    

    

print(c)
a, b = list(map(int, input().split()))
c = 0
for i in range(a, b + 1):
    new = list(reversed(list(str(i))))
    if new == list(str(i)):
        c += 1
print(c)

a, b = list(map(int, input().split()))
c = 0
for i in range(a, b + 1):
    if list(str(i)) == list(str(i))[::-1]:
        c += 1
print(c)

-    new = list(reversed(list(str(i)))) -    if new == list(str(i)): +    if list(str(i)) == list(str(i))[::-1]: