
# 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:

import math

N = int(eval(input()))

for i in range(int(math.sqrt(N))):

    if N % (int(math.sqrt(N))-i) == 0:

        print((int(N/(int(math.sqrt(N))-i)+int(math.sqrt(N))-i-2)))

        break

# optimized version of the same code:

import math

N = int(eval(input()))

M = int(math.sqrt(N))

for i in range(M):

    if N % (M-i) == 0:

        print((int(N/(M-i)+M-i-2)))

        break

import math

N = int(eval(input()))
for i in range(int(math.sqrt(N))):
    if N % (int(math.sqrt(N)) - i) == 0:
        print((int(N / (int(math.sqrt(N)) - i) + int(math.sqrt(N)) - i - 2)))
        break

import math

N = int(eval(input()))
M = int(math.sqrt(N))
for i in range(M):
    if N % (M - i) == 0:
        print((int(N / (M - i) + M - i - 2)))
        break

-for i in range(int(math.sqrt(N))): -    if N % (int(math.sqrt(N)) - i) == 0: -        print((int(N / (int(math.sqrt(N)) - i) + int(math.sqrt(N)) - i - 2))) +M = int(math.sqrt(N)) +for i in range(M): +    if N % (M - i) == 0: +        print((int(N / (M - i) + M - i - 2)))