from collections import deque


class RollingHash:
    def __init__(self, s: str):
        self.MOD = 998244353
        self.B = 1009
        self.h = 0
        self.deq = deque()
        for c in s:
            self.append(c)

    def append(self, c: str):
        assert len(c) == 1
        self.deq.append(ord(c))
        self.h = self.h * self.B + ord(c)
        self.h %= self.MOD

    def appendleft(self, c: str):
        assert len(c) == 1
        sz = len(self.deq)
        self.deq.appendleft(ord(c))
        self.h += ord(c) * pow(self.B, sz, self.MOD)
        self.h %= self.MOD

    def pop(self):
        assert len(self.deq) > 0
        inv_b = pow(self.B, self.MOD-2, self.MOD)
        v = self.deq.pop()
        self.h = (self.h - v) * inv_b % self.MOD

    def popleft(self):
        assert len(self.deq) > 0
        sz = len(self.deq)
        v = self.deq.popleft()
        self.h -= v * pow(self.B, sz-1, self.MOD)
        self.h %= self.MOD

    def hash(self) -> int:
        return self.h


S = input()

h = RollingHash(S)
r_h = RollingHash(S[::-1])
for i in range(len(S)):
    if h.hash() == r_h.hash():
        t = S[:i]
        ans = S + t[::-1]
        print(ans)
        break

    h.popleft()
    r_h.pop()