
# 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:

from collections import defaultdict

from bisect import bisect_left



s = eval(input())

n = len(s)

s = s + s

t = eval(input())

if set(t) - set(s):

	print((-1))

	exit()

d = defaultdict(list)

for i in range(2 * n):

	d[s[i]] += [i]

cur = tot = 0

for c in t:

	x = d[c][bisect_left(d[c], cur)]

	if x < n:

		cur = x + 1

	else:

		cur = x - n + 1

		tot += n

tot += cur

print(tot)


# optimized version of the same code:

from collections import defaultdict

from bisect import bisect_left





def main():

	s = eval(input())

	n = len(s)

	s = s + s

	t = eval(input())

	if set(t) - set(s):

		print((-1))

		exit()

	d = defaultdict(list)

	for i in range(2 * n):

		d[s[i]] += [i]

	cur = ncnt = 0



	for c in t:

		x = d[c][bisect_left(d[c], cur)]

		if x < n:

			cur = x + 1

		else:

			cur = x - n + 1

			ncnt += 1

	print((ncnt*n + cur))





if __name__ == "__main__":

	main()
from collections import defaultdict
from bisect import bisect_left

s = eval(input())
n = len(s)
s = s + s
t = eval(input())
if set(t) - set(s):
    print((-1))
    exit()
d = defaultdict(list)
for i in range(2 * n):
    d[s[i]] += [i]
cur = tot = 0
for c in t:
    x = d[c][bisect_left(d[c], cur)]
    if x < n:
        cur = x + 1
    else:
        cur = x - n + 1
        tot += n
tot += cur
print(tot)

from collections import defaultdict
from bisect import bisect_left


def main():
    s = eval(input())
    n = len(s)
    s = s + s
    t = eval(input())
    if set(t) - set(s):
        print((-1))
        exit()
    d = defaultdict(list)
    for i in range(2 * n):
        d[s[i]] += [i]
    cur = ncnt = 0
    for c in t:
        x = d[c][bisect_left(d[c], cur)]
        if x < n:
            cur = x + 1
        else:
            cur = x - n + 1
            ncnt += 1
    print((ncnt * n + cur))


if __name__ == "__main__":
    main()

-s = eval(input()) -n = len(s) -s = s + s -t = eval(input()) -if set(t) - set(s): -    print((-1)) -    exit() -d = defaultdict(list) -for i in range(2 * n): -    d[s[i]] += [i] -cur = tot = 0 -for c in t: -    x = d[c][bisect_left(d[c], cur)] -    if x < n: -        cur = x + 1 -    else: -        cur = x - n + 1 -        tot += n -tot += cur -print(tot) + +def main(): +    s = eval(input()) +    n = len(s) +    s = s + s +    t = eval(input()) +    if set(t) - set(s): +        print((-1)) +        exit() +    d = defaultdict(list) +    for i in range(2 * n): +        d[s[i]] += [i] +    cur = ncnt = 0 +    for c in t: +        x = d[c][bisect_left(d[c], cur)] +        if x < n: +            cur = x + 1 +        else: +            cur = x - n + 1 +            ncnt += 1 +    print((ncnt * n + cur)) + + +if __name__ == "__main__": +    main()