
# 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:

from numpy import*;_,a=open(0);print((*argsort(int32(a.split()))+1))

# optimized version of the same code:

n,a=open(0);a=a.split();print((*sorted(list(range(1,int(n)+1)),key=lambda x:int(a[x-1]))))
from numpy import *

_, a = open(0)
print((*argsort(int32(a.split())) + 1))

n, a = open(0)
a = a.split()
print((*sorted(list(range(1, int(n) + 1)), key=lambda x: int(a[x - 1]))))

-from numpy import * - -_, a = open(0) -print((*argsort(int32(a.split())) + 1)) +n, a = open(0) +a = a.split() +print((*sorted(list(range(1, int(n) + 1)), key=lambda x: int(a[x - 1]))))