A = input()
# A = 'aabcb'
# s = A + A[-2::-1]
# if len(A) % 2:
# n = len(A) // 2
j = 0
j = -1
for i in range(len(A)):
    # if A[i] == A[-j - 1]:
    if A[i] == A[j]:
        # j += 1
        j -= 1
    # elif j:
    elif j != -1:
        # j = 0
        j = -1

# ans = A + A[-j - 1::-1]
# ans = A + A[j::-1]
# print(ans)
print(A + A[j::-1])