
# 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 numpy as np

n = int(eval(input()))

a = np.array(list(map(int, input().split())))



print((*list([x + 1 for x in np.argsort(a)])))

# optimized version of the same code:

n = int(eval(input()))

m = [(x, 0) for x in range(1, n+1)]



for i, x in enumerate(map(int, input().split())):

  m[i] = (m[i][0], x)

m.sort(key=lambda x : x[1])

print((' '.join([str(x[0]) for x in m])))
import numpy as np

n = int(eval(input()))
a = np.array(list(map(int, input().split())))
print((*list([x + 1 for x in np.argsort(a)])))

n = int(eval(input()))
m = [(x, 0) for x in range(1, n + 1)]
for i, x in enumerate(map(int, input().split())):
    m[i] = (m[i][0], x)
m.sort(key=lambda x: x[1])
print((" ".join([str(x[0]) for x in m])))

-import numpy as np - -a = np.array(list(map(int, input().split()))) -print((*list([x + 1 for x in np.argsort(a)]))) +m = [(x, 0) for x in range(1, n + 1)] +for i, x in enumerate(map(int, input().split())): +    m[i] = (m[i][0], x) +m.sort(key=lambda x: x[1]) +print((" ".join([str(x[0]) for x in m])))