S=input()
l,ans=10**10,''
for i in range(len(S)+1):
  f=0
  SS=S+'!'*i
  for j in range(len(SS)):
    if SS[j]!='!' and SS[-1-j]!='!' and SS[j]!=SS[-1-j]:
      f=1
      break 
  if f==0:
    SS=list(SS)
    for j in range(len(SS)):
      if SS[-1-j]=='!':
        SS[-1-j]=S[j]
    ans=''.join(SS)
    print(ans)
    exit()