
# 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 collections import Counter,defaultdict,deque

from heapq import heappop,heappush,heapify

import sys,bisect,math,itertools,fractions,pprint

sys.setrecursionlimit(10**8)

mod = 10**9+7

INF = float('inf')

def inp(): return int(sys.stdin.readline())

def inpl(): return list(map(int, sys.stdin.readline().split()))



n = inp()

A = sorted(inpl())

B = sorted(inpl())

C = sorted(inpl())

cnt = [0] * n

res = 0

for i,b in enumerate(B):

    c = bisect.bisect_left(C,b+1)

    cnt[i] = n-c



acc = [0]

for x in cnt:

    acc += [acc[-1] + x]

su = sum(cnt) 

for i,a in enumerate(A):

    c = bisect.bisect_left(B,a+1)

    res += su - acc[c]

print(res)

# optimized version of the same code:

from collections import Counter,defaultdict,deque

from heapq import heappop,heappush,heapify

import sys,bisect,math,itertools,fractions,pprint

sys.setrecursionlimit(10**8)

mod = 10**9+7

INF = float('inf')

def inp(): return int(sys.stdin.readline())

def inpl(): return list(map(int, sys.stdin.readline().split()))



n = inp()

a = inpl()

b = inpl()

c = inpl()

a.sort()

b.sort()

c.sort()

lb = [0] * n

res = 0

for i in range(n):

    tmp = bisect.bisect_right(b,a[i])

    if tmp == n: continue

    lb[tmp] += 1

llb = list(itertools.accumulate(lb))

# print(lb,llb)

rr = [0] * n

for i in range(n):

    tmp = bisect.bisect_right(c,b[i])

    if tmp == n: continue

    rr[tmp] += llb[i]

print((sum(list(itertools.accumulate(rr)))))
from collections import Counter, defaultdict, deque
from heapq import heappop, heappush, heapify
import sys, bisect, math, itertools, fractions, pprint

sys.setrecursionlimit(10**8)
mod = 10**9 + 7
INF = float("inf")


def inp():
    return int(sys.stdin.readline())


def inpl():
    return list(map(int, sys.stdin.readline().split()))


n = inp()
A = sorted(inpl())
B = sorted(inpl())
C = sorted(inpl())
cnt = [0] * n
res = 0
for i, b in enumerate(B):
    c = bisect.bisect_left(C, b + 1)
    cnt[i] = n - c
acc = [0]
for x in cnt:
    acc += [acc[-1] + x]
su = sum(cnt)
for i, a in enumerate(A):
    c = bisect.bisect_left(B, a + 1)
    res += su - acc[c]
print(res)

from collections import Counter, defaultdict, deque
from heapq import heappop, heappush, heapify
import sys, bisect, math, itertools, fractions, pprint

sys.setrecursionlimit(10**8)
mod = 10**9 + 7
INF = float("inf")


def inp():
    return int(sys.stdin.readline())


def inpl():
    return list(map(int, sys.stdin.readline().split()))


n = inp()
a = inpl()
b = inpl()
c = inpl()
a.sort()
b.sort()
c.sort()
lb = [0] * n
res = 0
for i in range(n):
    tmp = bisect.bisect_right(b, a[i])
    if tmp == n:
        continue
    lb[tmp] += 1
llb = list(itertools.accumulate(lb))
# print(lb,llb)
rr = [0] * n
for i in range(n):
    tmp = bisect.bisect_right(c, b[i])
    if tmp == n:
        continue
    rr[tmp] += llb[i]
print((sum(list(itertools.accumulate(rr)))))

-A = sorted(inpl()) -B = sorted(inpl()) -C = sorted(inpl()) -cnt = [0] * n +a = inpl() +b = inpl() +c = inpl() +a.sort() +b.sort() +c.sort() +lb = [0] * n -for i, b in enumerate(B): -    c = bisect.bisect_left(C, b + 1) -    cnt[i] = n - c -acc = [0] -for x in cnt: -    acc += [acc[-1] + x] -su = sum(cnt) -for i, a in enumerate(A): -    c = bisect.bisect_left(B, a + 1) -    res += su - acc[c] -print(res) +for i in range(n): +    tmp = bisect.bisect_right(b, a[i]) +    if tmp == n: +        continue +    lb[tmp] += 1 +llb = list(itertools.accumulate(lb)) +# print(lb,llb) +rr = [0] * n +for i in range(n): +    tmp = bisect.bisect_right(c, b[i]) +    if tmp == n: +        continue +    rr[tmp] += llb[i] +print((sum(list(itertools.accumulate(rr)))))