
# 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:

def binarySearch():

    n = int(eval(input()))

    S = set(map(int, input().split()))

    q = int(eval(input()))

    T = set(map(int, input().split()))

    print((len(S.intersection(T))))

    



binarySearch()

# optimized version of the same code:

def binarySearch():

    n = int(eval(input()))

    S = set(input().split())

    q = int(eval(input()))

    T = set(input().split())

    print((len(S.intersection(T))))

    



binarySearch()
def binarySearch():
    n = int(eval(input()))
    S = set(map(int, input().split()))
    q = int(eval(input()))
    T = set(map(int, input().split()))
    print((len(S.intersection(T))))


binarySearch()

def binarySearch():
    n = int(eval(input()))
    S = set(input().split())
    q = int(eval(input()))
    T = set(input().split())
    print((len(S.intersection(T))))


binarySearch()

-    S = set(map(int, input().split())) +    S = set(input().split()) -    T = set(map(int, input().split())) +    T = set(input().split())