
# 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:

S = eval(input())

T = eval(input())

N = len(S)

cnt = 0

for i in range(N):

    cnt += (S[i] != T[i])



print(cnt)


# optimized version of the same code:

S = eval(input())

T = eval(input())

cnt = 0

for i in range(len(S)):

    cnt += (S[i] != T[i])



print(cnt)
S = eval(input())
T = eval(input())
N = len(S)
cnt = 0
for i in range(N):
    cnt += S[i] != T[i]
print(cnt)

S = eval(input())
T = eval(input())
cnt = 0
for i in range(len(S)):
    cnt += S[i] != T[i]
print(cnt)

-N = len(S) -for i in range(N): +for i in range(len(S)):