#include<fstream>
#define NX 550

using namespace std;

ifstream f("palm.in");
ofstream g("palm.out");

char c[NX];
int lg,maxa;

void read();
void solvepar();
void solveimp();

int main()
{
	
	read();
	lg=strlen(c);
	
	solveimp();
	solvepar();
	
	g<<maxa;
	
	f.close();
	g.close();
	return 1;
}

void read()
{
	f.getline(c,NX);
}

void solveimp()
{
	int i,j,k,nr;
	for (i=0;i<lg;++i)
	{
		j=i-1;
		k=i+1;
		nr=1;
		while (j>-1&&k<lg)
		{
			if (c[j]==c[k]&&c[j]<=c[i])
				nr+=2;
			else break;
			++k;
			--j;
		}
		if (nr>maxa) maxa=nr;
	}
}

void solvepar()
{
	int i,j,k,nr;
	for (i=0;i<lg-1;++i)
		if (c[i]==c[i+1])
		{
			nr=2;
			j=i-1;
			k=i+2;
			while (j>-1&&k<lg)
			{
				if (c[j]==c[k]&&c[j]<=c[i])
					nr+=2;
				else break;
				++k;
				--j;
			}
			if (nr>maxa) maxa=nr;
		}
}