
# 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:

a, b = list(map(int, input().strip().split(" ")))

count = 0

for i in range(a, b + 1):

    if str(i) == str(i)[::-1]:

        count += 1

print(count)


# optimized version of the same code:

def solve(string):

    a, b = list(map(int, string.split()))

    count = 0

    for i in range(a, b + 1):

        if str(i) == str(i)[::-1]:

            count += 1

    return str(count)





if __name__ == '__main__':

    print((solve(eval(input()))))

a, b = list(map(int, input().strip().split(" ")))
count = 0
for i in range(a, b + 1):
    if str(i) == str(i)[::-1]:
        count += 1
print(count)

def solve(string):
    a, b = list(map(int, string.split()))
    count = 0
    for i in range(a, b + 1):
        if str(i) == str(i)[::-1]:
            count += 1
    return str(count)


if __name__ == "__main__":
    print((solve(eval(input()))))

-a, b = list(map(int, input().strip().split(" "))) -count = 0 -for i in range(a, b + 1): -    if str(i) == str(i)[::-1]: -        count += 1 -print(count) +def solve(string): +    a, b = list(map(int, string.split())) +    count = 0 +    for i in range(a, b + 1): +        if str(i) == str(i)[::-1]: +            count += 1 +    return str(count) + + +if __name__ == "__main__": +    print((solve(eval(input()))))