#define N 110050
#define M 100005
#define maxn 205
#define MOD 1000000000000000007
void Manacher(char str[],int len){
    char tstr[N+N];
    int p[N + N],l2 =0,mi;
    tstr[l2++] = '#';
    for(int i =0;i<len;i++){
        tstr[l2++] = str[i];
        tstr[l2++] = '#';
    }
    p[0] = 0;mi = 0;
    for(int i = 1;i<l2;i++){
        int mi2 = mi + mi - i;
        if(mi + p[mi] >= i) p[i] = min(mi2 - (mi - p[mi]),p[mi2]);
        else p[i] = 0;
        if(p[i] == 0 ||  mi2 - p[mi2] == mi - p[mi]){
            int maxx = p[i]+1;
            while(i- maxx >= 0 && i+maxx < l2 && tstr[i-maxx] == tstr[i+maxx]){
                maxx++;
            }
            p[i] = maxx - 1;
        }
        if(p[i] + i > p[mi] + mi) mi = i;
    }
    int ans = -1;
    for(int i = 0;i < l2;i++){
        ans = max(ans,p[i]);
    }
    printf("%d\n",ans);
}
int main()
{
    char str[N];
    while(SS(str)!=EOF){
        Manacher(str,strlen(str));
    }
    return 0;
}