
# 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:

x = int(eval(input()))

print((0 if x==1 else 1))

# optimized version of the same code:

s = eval(input())

if s == '0':

  print((1))

else:

  print((0))
x = int(eval(input()))
print((0 if x == 1 else 1))

s = eval(input())
if s == "0":
    print((1))
else:
    print((0))

-x = int(eval(input())) -print((0 if x == 1 else 1)) +s = eval(input()) +if s == "0": +    print((1)) +else: +    print((0))