
# 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()))

s=np.argsort(np.array(list(map(int,input().split()))))+1

print((*s))

# optimized version of the same code:

n=int(eval(input()))

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

l=sorted([[inx+1,j] for inx,j in enumerate(a)],key=lambda x:x[1])

ans=[i for i,j in l]

print((*ans))
import numpy as np

n = int(eval(input()))
s = np.argsort(np.array(list(map(int, input().split())))) + 1
print((*s))

n = int(eval(input()))
a = list(map(int, input().split()))
l = sorted([[inx + 1, j] for inx, j in enumerate(a)], key=lambda x: x[1])
ans = [i for i, j in l]
print((*ans))

-import numpy as np - -s = np.argsort(np.array(list(map(int, input().split())))) + 1 -print((*s)) +a = list(map(int, input().split())) +l = sorted([[inx + 1, j] for inx, j in enumerate(a)], key=lambda x: x[1]) +ans = [i for i, j in l] +print((*ans))