
# 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:

while True:

    (n, x) = [int(i) for i in input().split()]

    if n == x == 0:

        break



    count = 0

    for a in range(1, n + 1):

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

            for c in range(b + 1, n + 1):

                if sum([a,b,c]) == x:

                    count += 1



    print(count)

# optimized version of the same code:

while True:

    (n, x) = [int(i) for i in input().split()]

    if n == x == 0:

        break



    count = 0

    limit = n if n < x else x

    for a in range(1, limit + 1):

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

            for c in range(b + 1, limit + 1):

                if sum([a,b,c]) == x:

                    count += 1



    print(count)
while True:
    (n, x) = [int(i) for i in input().split()]
    if n == x == 0:
        break
    count = 0
    for a in range(1, n + 1):
        for b in range(a + 1, n + 1):
            for c in range(b + 1, n + 1):
                if sum([a, b, c]) == x:
                    count += 1
    print(count)

while True:
    (n, x) = [int(i) for i in input().split()]
    if n == x == 0:
        break
    count = 0
    limit = n if n < x else x
    for a in range(1, limit + 1):
        for b in range(a + 1, limit + 1):
            for c in range(b + 1, limit + 1):
                if sum([a, b, c]) == x:
                    count += 1
    print(count)

-    for a in range(1, n + 1): -        for b in range(a + 1, n + 1): -            for c in range(b + 1, n + 1): +    limit = n if n < x else x +    for a in range(1, limit + 1): +        for b in range(a + 1, limit + 1): +            for c in range(b + 1, limit + 1):