
# 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().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:

A, B = list(map(int, input().split()))

count = 0

for i in range(10):

    for j in range(10):

        for k in range(10):

            if(A <= 10000*i + 1000*j + 100*k + 10*j +i <= B):

                count += 1

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

A, B = list(map(int, input().split()))
count = 0
for i in range(10):
    for j in range(10):
        for k in range(10):
            if A <= 10000 * i + 1000 * j + 100 * k + 10 * j + i <= B:
                count += 1
print(count)

-for i in range(A, B + 1): -    if str(i) == str(i)[::-1]: -        count += 1 +for i in range(10): +    for j in range(10): +        for k in range(10): +            if A <= 10000 * i + 1000 * j + 100 * k + 10 * j + i <= B: +                count += 1