
# 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 sys import stdin

def solve():

    s = int(stdin.readline())

    mod = 10**9+7

    if s < 3: return 0

    dp = [0]*(s+1)

    dp[0] = 1

    for i in range(3,s+1):

        for x in range(3,i+1):

            if x in [i-1,i-2]:

                continue

            dp[i] += dp[i-x]

    return dp[s]%mod

print((solve()))

# optimized version of the same code:

from sys import stdin

def solve():

    s = int(stdin.readline())

    mod = 10**9+7

    if s < 3: return 0

    dp = [0]*(s+1)

    dp[0] = 1

    for i in range(3,s+1):

        dp[i] = dp[i-1] + dp[i-3]

    return dp[s]%mod

print((solve()))
from sys import stdin


def solve():
    s = int(stdin.readline())
    mod = 10**9 + 7
    if s < 3:
        return 0
    dp = [0] * (s + 1)
    dp[0] = 1
    for i in range(3, s + 1):
        for x in range(3, i + 1):
            if x in [i - 1, i - 2]:
                continue
            dp[i] += dp[i - x]
    return dp[s] % mod


print((solve()))

from sys import stdin


def solve():
    s = int(stdin.readline())
    mod = 10**9 + 7
    if s < 3:
        return 0
    dp = [0] * (s + 1)
    dp[0] = 1
    for i in range(3, s + 1):
        dp[i] = dp[i - 1] + dp[i - 3]
    return dp[s] % mod


print((solve()))

-        for x in range(3, i + 1): -            if x in [i - 1, i - 2]: -                continue -            dp[i] += dp[i - x] +        dp[i] = dp[i - 1] + dp[i - 3]