
# 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 sys

input = sys.stdin.readline

sys.setrecursionlimit(10 ** 7)



K, S = list(map(int, input().split()))



ans = 0

for z in range(K+1):

    for y in range(K+1):

        x = S - (z + y)

        if x >= 0 and x <= K:

            ans += 1

print(ans)

# optimized version of the same code:

import sys

input = sys.stdin.readline

sys.setrecursionlimit(10 ** 7)



K, S = list(map(int, input().split()))



ans = 0

for z in range(K+1):

    for y in range(K+1):

        x = S - (z + y)

        if 0 <= x <= K:

            ans += 1

print(ans)
import sys

input = sys.stdin.readline
sys.setrecursionlimit(10**7)
K, S = list(map(int, input().split()))
ans = 0
for z in range(K + 1):
    for y in range(K + 1):
        x = S - (z + y)
        if x >= 0 and x <= K:
            ans += 1
print(ans)

import sys

input = sys.stdin.readline
sys.setrecursionlimit(10**7)
K, S = list(map(int, input().split()))
ans = 0
for z in range(K + 1):
    for y in range(K + 1):
        x = S - (z + y)
        if 0 <= x <= K:
            ans += 1
print(ans)

-        if x >= 0 and x <= K: +        if 0 <= x <= K: