#include<stdio.h>
char a[200];
int pan(int a,int b);
int main()
{
	scanf("%s",a);
	int x=0;
	for(;a[x]!='\0';x++);
	int ans=x;
	while(pan(0,x-1))
	{
		ans/=2;
		x/=2;
	}
	printf("%d",ans);
	return 0;
}
int pan(int m,int n)
{
    int mid=(m+n)/2;
    for(int i=m;i<=mid;i++)
    if(a[i]!=a[n-i]) return 0;
    return 1;
}
/**************************************************************
	Problem: 1134
	User: admin
	Language: C
	Result: Accepted
	Time:8 ms
	Memory:1144 kb
****************************************************************/