
# 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:

N, W = list(map(int, input().split()))

items = sorted([list(map(int, input().split())) for i in range(N)])



# dp1[i][j] := 商品0 ~ i が対象

dp = [[0] * (W + 1) for i in range(N + 1)]



# dpテーブルを埋める

for i in range(N):

    wi, vi = items[i]

    for j in range(W + 1):

        if j + wi <= W:

            dp[i + 1][j + wi] = max(dp[i + 1][j + wi], dp[i][j] + vi)

        dp[i + 1][j] = max(dp[i][j], dp[i + 1][j])





ans = 0

for i, (wi, vi) in enumerate(items):

    for j in range(W):

        ans = max(ans, dp[i][j] + vi)



print(ans)


# optimized version of the same code:

N, W = list(map(int, input().split()))

items = sorted([list(map(int, input().split())) for i in range(N)])



# dp1[i][j] := 商品0 ~ i が対象

dp = [[0] * (W + 1) for i in range(N + 1)]



# dpテーブルを埋める

for i in range(N):

    wi, vi = items[i]

    for j in range(W + 1):

        if j + wi <= W:

            dp[i + 1][j + wi] = max(dp[i + 1][j + wi], dp[i][j] + vi)

        dp[i + 1][j] = max(dp[i][j], dp[i + 1][j])





ans = 0

for i, (wi, vi) in enumerate(items):

    ans = max(ans, dp[i][W - 1] + vi)



print(ans)

N, W = list(map(int, input().split()))
items = sorted([list(map(int, input().split())) for i in range(N)])
# dp1[i][j] := 商品0 ~ i が対象
dp = [[0] * (W + 1) for i in range(N + 1)]
# dpテーブルを埋める
for i in range(N):
    wi, vi = items[i]
    for j in range(W + 1):
        if j + wi <= W:
            dp[i + 1][j + wi] = max(dp[i + 1][j + wi], dp[i][j] + vi)
        dp[i + 1][j] = max(dp[i][j], dp[i + 1][j])
ans = 0
for i, (wi, vi) in enumerate(items):
    for j in range(W):
        ans = max(ans, dp[i][j] + vi)
print(ans)

N, W = list(map(int, input().split()))
items = sorted([list(map(int, input().split())) for i in range(N)])
# dp1[i][j] := 商品0 ~ i が対象
dp = [[0] * (W + 1) for i in range(N + 1)]
# dpテーブルを埋める
for i in range(N):
    wi, vi = items[i]
    for j in range(W + 1):
        if j + wi <= W:
            dp[i + 1][j + wi] = max(dp[i + 1][j + wi], dp[i][j] + vi)
        dp[i + 1][j] = max(dp[i][j], dp[i + 1][j])
ans = 0
for i, (wi, vi) in enumerate(items):
    ans = max(ans, dp[i][W - 1] + vi)
print(ans)

-    for j in range(W): -        ans = max(ans, dp[i][j] + vi) +    ans = max(ans, dp[i][W - 1] + vi)