
# 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:

# coding: utf-8

import sys

import numpy as np



sr = lambda: sys.stdin.readline().rstrip()

ir = lambda: int(sr())

lr = lambda: list(map(int, sr().split()))



N = ir()

V = np.array(lr())

C = np.array(lr())

V -= C

V = V[V>0]

answer = V.sum()

print(answer)


# optimized version of the same code:

# coding: utf-8

import sys



sr = lambda: sys.stdin.readline().rstrip()

ir = lambda: int(sr())

lr = lambda: list(map(int, sr().split()))



N = ir()

V = lr()

C = lr()

total = 0

for i in range(N):

    result = V[i] - C[i]

    if result > 0:

        total += result



print(total)

# coding: utf-8
import sys
import numpy as np

sr = lambda: sys.stdin.readline().rstrip()
ir = lambda: int(sr())
lr = lambda: list(map(int, sr().split()))
N = ir()
V = np.array(lr())
C = np.array(lr())
V -= C
V = V[V > 0]
answer = V.sum()
print(answer)

# coding: utf-8
import sys

sr = lambda: sys.stdin.readline().rstrip()
ir = lambda: int(sr())
lr = lambda: list(map(int, sr().split()))
N = ir()
V = lr()
C = lr()
total = 0
for i in range(N):
    result = V[i] - C[i]
    if result > 0:
        total += result
print(total)

-import numpy as np -V = np.array(lr()) -C = np.array(lr()) -V -= C -V = V[V > 0] -answer = V.sum() -print(answer) +V = lr() +C = lr() +total = 0 +for i in range(N): +    result = V[i] - C[i] +    if result > 0: +        total += result +print(total)