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

using i64 = long long;
using u64 = unsigned long long;

struct debug {
#define contPrint { *this << "["; \
        int f = 0; for(auto it : x) { *this << (f?", ":""); *this << it; f = 1;} \
        *this << "]"; return *this;}
 
    ~debug(){cerr << endl;}
    template<class c> debug& operator<<(c x) {cerr << x; return *this;}
    template<class c, class d>
    debug& operator<<(pair<c, d> x) {*this << "(" << x.first << ", " << x.second << ")"; 
        return *this;}
    template<class c> debug& operator<<(vector<c> x) contPrint;
#undef contPrint
};

#define dbg(x) "[" << #x << ": " << x << "]  "
#define Wa() cerr << "[LINE: " << __LINE__ << "] -> "; debug() << 
#define FASTIO ios_base::sync_with_stdio(false); cin.tie(NULL);

vector<int> manachar(string s)
{
    string t;
    for(char c : s) {
        t += string("#") + c;
    }
    t += '#';
    s = t;

    int n = (int)s.size();
    s = "$" + s + "^";
    vector<int> p(n+2);
    int l = 1, r = 1;
    for(int i = 1; i <= n; i++) {
        p[i] = max(0, min(r - i, p[l + (r - i)]));
        while(s[i - p[i]] == s[i + p[i]]) {
            p[i]++;
        }
        if(i + p[i] > r) {
            l = i - p[i], r = i + p[i];
        }
    }

    vector<int> ret;
    for(int i = 3; i < (int)s.length(); i += 2) {
        ret.push_back(p[i] / 2);
    }
    return ret;
}

const int N = 4e6 + 6;
char ch[N];

int main() 
{
    scanf("%s", ch);
    int len = strlen(ch);

    vector<int> p = manachar(ch);

    int start = 0;
    for(int i = 0; i < len; i++) {
        if(p[i] >= (i - start + 1)) {
            start = i + 1;
        }
    }

    int last = len-1;
    for(int i = len-2; i >= start; i--) {
        int l = last - i;
        if(p[i] >= l && l <= (i - start + 1)) {
            last = i;
        }
    }

    printf("%d\n", last - start + 1);
}