#include <stdio.h>
#include <iostream>
#include <algorithm>
#include <bits/stdc++.h>
#define LL long long
using namespace std;

#define L(i, s, t) for(int i = s; i <= t; ++i)
#define R(i, t, s) for(int i = t; i >= s; --i)

void read(int &x) {
    x = 0; int w = 1; char c = getchar(); for(; c < '0' || c > '9'; c = getchar()) if (c == '-') w = -1;
    for(; c <= '9' && c >= '0'; c = getchar()) x = x * 10 + c - '0'; x *= w;
}

const int N = 4e6;

char s[N + 5], t[2 * N + 5]; int n, p[2 * N + 5];
int rb[N + 5], lb[N + 5];
int main() {
	// freopen("t.in", "r", stdin);
	scanf("%s", s + 1);
	n = strlen(s + 1);int m = 0; t[0] = '@';
	for(int i = 1; i <= n; ++i)
		{t[++m] = s[i]; t[++m] = '#';}
	t[++m] = '#'; t[++m] == '!';

	int r = 0, d = 0;
	for(int i = 1; i <= m; ++i) {
		if (i > r) p[i] = 1; else p[i] = min(r - i + 1, p[2 * d - i]);
		while(t[i - p[i]] == t[i + p[i]]) ++p[i];
		if (i + p[i] - 1> r) {
			r = i + p[i] - 1;
			d = i;
		}
	}
	r = n; rb[n] = 1;
	for(int i = n - 1; i >= 1; --i) {
		if (p[2 * i] / 2 >= r - i) {
			r = i;
			// cout << "fc" << p[2 * i] i << endl;
			rb[i] = 1;
		}
	}

	// cout << p[2 * i] << endl;
	int l = 1; lb[1] = 1;
	for(int i = 2; i <= n; ++i)
		if (p[2 * (i - 1)] / 2 >= i - l) {
			l = i;
			lb[i] = 1;
		}

	int ans = n, lmx = 0;
	for(int i = 1; i <= n; ++i) {
		if (lb[i]) lmx = i;
		if (rb[i]) ans = min(ans, i - lmx + 1);
	}
	printf("%d\n", ans);
    return 0;
}