#include <iostream>
#include <vector>
#include <string>

using namespace std;

int main() {

string s;
int ans = 0,l = 0;

cin >> s;

for(int i = 1;i < s.length();i++){
    l = 0;
    if(s[i] == s[i+1]){
        int j = 1;
        l = 2;
        while(1){
            j++;
            if(s[i-j+1] != s[i+j]) break;
            l += 2;
        }
    }else if(s[i-1] == s[i+1]){
        int j = 1;
        l = 3;
        while(1){
            j++;
            if(s[i-j] != s[i+j]) break;
            l += 2;
        }
    }
    ans = max(l,ans);
}

cout << ans << endl;

return 0;
}