#include <bits/stdc++.h>
#ifdef LOCAL
#include "cp_debug.h"
#else
#define debug(...) 42
#endif
#define rep(i,a,b) for(int i = a; i < b; ++i)
#define all(x) begin(x), end(x)
#define sz(x) (int)x.size()
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<ll> vl;

template<typename T> void read(T &x){
    x = 0;char ch = getchar();ll f = 1;
    while(!isdigit(ch)){if(ch == '-')f*=-1;ch=getchar();}
    while(isdigit(ch)){x = x*10+ch-48;ch=getchar();}x*=f;
}
template<typename T, typename... Args> void read(T &first, Args& ... args) {
    read(first);
    read(args...);
}
template<typename T> void write(T x) {
    if(x > 9) write(x/10);
    putchar(x%10 + '0');
}


array<vi, 2> manacher(const string& s) {
    int n = sz(s);
    array<vi,2> p = {vi(n+1), vi(n)};
    rep(z,0,2) for (int i=0,l=0,r=0; i < n; i++) {
        int t = r-i+!z;
        if (i<r) p[z][i] = min(t, p[z][l+t]);
        int L = i-p[z][i], R = i+p[z][i]-!z;
        while (L>=1 && R+1<n && s[L-1] == s[R+1])
            p[z][i]++, L--, R++;
        if (R>r) l=L, r=R;
    }
    return p;
}

void solve() {
    string s;
    cin >> s;
    int n = sz(s);
    auto ma = manacher(s);
    debug(ma[0]);
    vi lpos = {0}, rpos = {n};
    {
        int cl = 0;
        for(;;) {
            bool ok = false;
            for(int i = 1; cl+2*i<=n; i++) if(ma[0][cl+i] >= i) {
                lpos.push_back(cl+i);
                cl += i;
                ok = true;
                break;
            }
            if(!ok) break;
        }
    }
    debug(lpos);
    int ans = n;
    {
        int cr = n, lptr = sz(lpos)-1;
        ans = min(ans, n-lpos[lptr]);
        for(;;) {
            bool ok = false;
            for(int i = 1; cr-2*i>=0; i++) if(ma[0][cr-i] >= i) {
                rpos.push_back(cr-i);
                cr -= i;
                ok = true;
                while(lptr >= 0 && cr <= lpos[lptr]) lptr--;
                if(lptr >= 0) {
                    assert(cr > lpos[lptr]);
                    ans = min(ans, cr-lpos[lptr]);
                }
                break;
            }
            if(!ok) break;
        }
    }
    debug(rpos);
    cout<<ans<<'\n';
}

signed main() {
    int T; T = 1;
    while(T--) solve();
    return 0;
}