#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

string s,t;
int n,r[8000015];

int solve(){
    n = s.length();
    string t = "";
    t = t + '#' + '$';
    memset(r,0,sizeof(r));
    for(int i = 0;i < n;i ++){
        t += s[i];
        t += '$';
    }
    t += '@';
    int rmx = 0,id;
    for(int i = 1;i <= t.length() - 2;i ++){
        if(i < rmx) r[i] = min(rmx - i,r[(id << 1) - i]);
        else r[i] = 1;
        while(t[i - r[i]] == t[i + r[i]]) r[i] ++;
        if(i + r[i] > rmx){
            rmx = i + r[i];
            id = i;
        }
    }
    // cout << t << '\n';
    // for(int i = 0;i < t.length();i ++) cout << r[i]; cout << '\n';
    // manacher
    int ll = 1,rr = n;
    for(int i = n;i >= 1;i --){
        if((rr - i + 1) & 1) continue;
        int pos = 2 * (i + (rr - i) / 2) + 1;
        if(r[pos] / 2 >= (rr - i + 1) / 2){
            rr = i + (rr - i) / 2;
            i = rr;
        }
    }
    for(int i = 1;i <= rr;i ++){
        if((i - ll + 1) & 1) continue;
        int pos = 2 * (ll + (i - ll) / 2) + 1;
        if(r[pos] / 2 >= (i - ll + 1) / 2){
            ll = ll + (i - ll) / 2 + 1;
            i = ll;
        }
    }
    return rr - ll + 1;
}

int main(){
    ios::sync_with_stdio(false);
    cin >> s;
    int ans = solve();
    reverse(s.begin(),s.end());
    ans = min(ans,solve());
    cout << ans << '\n';
    return 0;
}