
# 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()))

A = [0] + list(map(int, input().split()))



A = np.array(A, dtype = np.int64)

A = np.cumsum(A)



dp = np.zeros((N, N), dtype = np.int64)



for j in range(1, N):

    for i in range(N - j):

        # print (dp[i, i:i + j], dp[i + 1:i + j + 1, i + j])

        tmp = min(dp[i, i:i + j] + dp[i + 1:i + j + 1, i + j])

        dp[i][i + j] = tmp + A[i + j + 1] - A[i]



print((dp[0][N - 1]))

# optimized version of the same code:

N = int(eval(input()))

A = [0] + list(map(int, input().split()))



INF = 10 ** 18



dp = [[0] * (N) for _ in range(N)]



for i in range(N):

    A[i + 1] += A[i]



for j in range(1, N):

    for i in range(N - j):

        tmp = INF

        for k in range(i, i + j):

            # print (i, i + j, k + 1)

            tmp = min(tmp, dp[i][k] + dp[k + 1][i + j])

        dp[i][i + j] = tmp + A[i + j + 1] - A[i]



print((dp[0][N - 1]))

import numpy as np

N = int(eval(input()))
A = [0] + list(map(int, input().split()))
A = np.array(A, dtype=np.int64)
A = np.cumsum(A)
dp = np.zeros((N, N), dtype=np.int64)
for j in range(1, N):
    for i in range(N - j):
        # print (dp[i, i:i + j], dp[i + 1:i + j + 1, i + j])
        tmp = min(dp[i, i : i + j] + dp[i + 1 : i + j + 1, i + j])
        dp[i][i + j] = tmp + A[i + j + 1] - A[i]
print((dp[0][N - 1]))

N = int(eval(input()))
A = [0] + list(map(int, input().split()))
INF = 10**18
dp = [[0] * (N) for _ in range(N)]
for i in range(N):
    A[i + 1] += A[i]
for j in range(1, N):
    for i in range(N - j):
        tmp = INF
        for k in range(i, i + j):
            # print (i, i + j, k + 1)
            tmp = min(tmp, dp[i][k] + dp[k + 1][i + j])
        dp[i][i + j] = tmp + A[i + j + 1] - A[i]
print((dp[0][N - 1]))

-import numpy as np - -A = np.array(A, dtype=np.int64) -A = np.cumsum(A) -dp = np.zeros((N, N), dtype=np.int64) +INF = 10**18 +dp = [[0] * (N) for _ in range(N)] +for i in range(N): +    A[i + 1] += A[i] -        # print (dp[i, i:i + j], dp[i + 1:i + j + 1, i + j]) -        tmp = min(dp[i, i : i + j] + dp[i + 1 : i + j + 1, i + j]) +        tmp = INF +        for k in range(i, i + j): +            # print (i, i + j, k + 1) +            tmp = min(tmp, dp[i][k] + dp[k + 1][i + j])