
# 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, m = list(map(int, input().split()))



d = np.ones((n, n)) * 1001



es = []

for i in range(m):

    es.append(list(map(int, input().split())))



for (i, j, w) in es:

    d[i - 1][j - 1] = w

    d[j - 1][i - 1] = w





for k in range(n):

    for i in range(n):

        for j in range(n):

            l = d[i][k] + d[k][j]

            if d[i][j] > l:

                d[i][j] = l



c = 0

for (i, j, w) in es:

    if d[i - 1][j - 1] < w:

        c += 1



print(c)


# optimized version of the same code:

n, m = list(map(int, input().split()))



d = [[1001] * n for i in range(n)]



es = []

for i in range(m):

    es.append(list(map(int, input().split())))



for (i, j, w) in es:

    d[i - 1][j - 1] = w

    d[j - 1][i - 1] = w





for k in range(n):

    for i in range(n):

        for j in range(n):

            l = d[i][k] + d[k][j]

            if d[i][j] > l:

                d[i][j] = l



c = 0

for (i, j, w) in es:

    if d[i - 1][j - 1] < w:

        c += 1



print(c)
import numpy as np

n, m = list(map(int, input().split()))
d = np.ones((n, n)) * 1001
es = []
for i in range(m):
    es.append(list(map(int, input().split())))
for (i, j, w) in es:
    d[i - 1][j - 1] = w
    d[j - 1][i - 1] = w
for k in range(n):
    for i in range(n):
        for j in range(n):
            l = d[i][k] + d[k][j]
            if d[i][j] > l:
                d[i][j] = l
c = 0
for (i, j, w) in es:
    if d[i - 1][j - 1] < w:
        c += 1
print(c)

n, m = list(map(int, input().split()))
d = [[1001] * n for i in range(n)]
es = []
for i in range(m):
    es.append(list(map(int, input().split())))
for (i, j, w) in es:
    d[i - 1][j - 1] = w
    d[j - 1][i - 1] = w
for k in range(n):
    for i in range(n):
        for j in range(n):
            l = d[i][k] + d[k][j]
            if d[i][j] > l:
                d[i][j] = l
c = 0
for (i, j, w) in es:
    if d[i - 1][j - 1] < w:
        c += 1
print(c)

-import numpy as np - -d = np.ones((n, n)) * 1001 +d = [[1001] * n for i in range(n)]