#include <set>
#include <map>
#include <deque>
#include <cmath>
#include <queue>
#include <string>
#include <vector>
#include <iostream>
#include <algorithm>

#define pb push_back
#define po pop_back()
#define matrix vector<vector<ll>>
#define pin(p) cin >> p.first >> p.second;
#define mx(v) max_element(v.begin(), v.end());
#define mn(v) min_element(v.begin(), v.end());
#define pout(p) cout << p.first << " " << p.second;
#define er(v, l, r) erase(v.begin() + l, v.begin() + r);
#define vin(v, n) for(int i = 0; i < n; ++i) cin >> v[i];
#define vout(v, n) for(int i = 0; i < n; ++i) cout << v[i];

using namespace std;

typedef long long ll;
typedef long long ld;

const ll INF = 1000LL * 1000 * 1000 * 1000 * 1000 * 1000;
const int inf = 1000 * 1000 * 1000;
vector<ll> hashe(100000);
vector<ll> power(100000);
ll truehash(int l, int r)
{
	return hashe[r + 1] - hashe[l] * power[r - l + 1];
}
bool turehash(int len,string &s)
{
	return len <= s.size() / 2 ? truehash(0, len - 1) == truehash(len, len * 2 - 1) : true;
}
int main()
{
	string s;
	cin >> s;
	s.insert(s.begin(), '#');
	hashe[0] = 0;
	power[0] = 1;
	for (int i = 1; i < s.size(); ++i)
	{
		power[i] = power[i - 1] * 29;
		hashe[i] = hashe[i - 1] + (s[i] - 'a' + 1)*power[i];
	}
	for (int k = 1; k < s.size(); ++k)
	{
		if (turehash(k,s))
		{
			cout << k;
			return  0;
		}
	}
	cout << s.size()-1;
	system("pause");
}