#include<stdio.h>
char s[505];
int main()
{
	freopen("palm.in","r",stdin);
	freopen("palm.out","w",stdout);
	int n,i,st,dr,lmax=1,l;
	s[0]='z'+1;
	i=0;
	while(scanf("%c",&s[++i])!=EOF)
	{
	}
	n=i;
	s[i+1]='z'+1;
	for(i=2;i<=n;i++)
	{
		if(s[i]==s[i+1])
		{
			st=i-1;
			dr=i+2;
			l=2;
			while(s[st]==s[dr]&&s[st]<=s[st+1])
			{
				l=l+2;
				st--;
				dr++;
			}
			if(l>lmax)
				lmax=l;
		}
		else
		{
			l=1;
			st=i-1;
			dr=i+1;
			while(s[st]==s[dr]&&s[st]<=s[st+1])
			{
				l=l+2;
				st--;
				dr++;
			}
			if(l>lmax)
				lmax=l;
		}
	}
printf("%d\n",lmax);	
return 0;
}