
# 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,c=list(map(int,input().split()))

e=(a-b)|(b-c)

print((bool(e|(a|b|c)%2)*(e^~-e).bit_length()-1))

# optimized version of the same code:

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

e=(a-b)|(b-c)

print((bool(e|b%2)*(e^~-e).bit_length()-1))
a, b, c = list(map(int, input().split()))
e = (a - b) | (b - c)
print((bool(e | (a | b | c) % 2) * (e ^ ~-e).bit_length() - 1))

a, b, c = list(map(int, input().split()))
e = (a - b) | (b - c)
print((bool(e | b % 2) * (e ^ ~-e).bit_length() - 1))

-print((bool(e | (a | b | c) % 2) * (e ^ ~-e).bit_length() - 1)) +print((bool(e | b % 2) * (e ^ ~-e).bit_length() - 1))