
# 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:

	k=list(map(int,input().split(" ")))

	if k[0]==k[1]==0:

		break

	ct=0

	a=0

	b=0

	c=0	

	max=k[0]

	sum=k[1]

	a=max+1

	

	while True:

		a-=1

		b=a-1

		c=sum-a-b

		if not a>b>c:

			print(ct)

			break

		while a>b>c:

			if a>b>c>0:

				ct+=1

			b-=1

			c+=1

			

# optimized version of the same code:

while True:

	k=list(map(int,input().split(" ")))

	if k[0]==k[1]==0:

		break

	ct=0

	a=0

	b=0

	c=0	

	max=k[0]

	sum=k[1]

	a=max+1

	while True:

		a-=1

		b=a-1

		c=sum-a-b

		if not a>c:

			print(ct)

			break

		while b>c:

			if c>0:

				ct+=1

			b-=1

			c+=1
while True:
    k = list(map(int, input().split(" ")))
    if k[0] == k[1] == 0:
        break
    ct = 0
    a = 0
    b = 0
    c = 0
    max = k[0]
    sum = k[1]
    a = max + 1
    while True:
        a -= 1
        b = a - 1
        c = sum - a - b
        if not a > b > c:
            print(ct)
            break
        while a > b > c:
            if a > b > c > 0:
                ct += 1
            b -= 1
            c += 1

while True:
    k = list(map(int, input().split(" ")))
    if k[0] == k[1] == 0:
        break
    ct = 0
    a = 0
    b = 0
    c = 0
    max = k[0]
    sum = k[1]
    a = max + 1
    while True:
        a -= 1
        b = a - 1
        c = sum - a - b
        if not a > c:
            print(ct)
            break
        while b > c:
            if c > 0:
                ct += 1
            b -= 1
            c += 1

-        if not a > b > c: +        if not a > c: -        while a > b > c: -            if a > b > c > 0: +        while b > c: +            if c > 0: