#include <fstream>
#include <string>
using namespace std;
string s;
int L[505][30], D[505][30];
int main(){
	ifstream fin("palm.in");
	ofstream fout("palm.out");
	int i, n, j;
	fin >> s;
	n = s.size();
	for(i = 0; i < n; ++i){
		if(i)
		for(j = 1; j <= 'z' - 'a' + 1; ++j)
			L[i][j] = L[i - 1][j];
		L[i][s[i] - 'a' + 1] = L[i][s[i] - 'a'] + 1;
	}
	for(i = n - 1; i >= 0; --i){
		for(j = 1; j <= 'z' - 'a' + 1; ++j)
			D[i][j] = D[i + 1][j];
		D[i][s[i] - 'a' + 1] = D[i][s[i] - 'a'] + 1;
	}
	
	int max = 0;
//	for(i = 0; i < n; ++i){
//		for(j = 1; j <= 'z' - 'a' + 1; ++j)
//			if(D[i][j])
//				fout << i << " " << (char)(j + 'a' - 1) << " "  << D[i][j] << '\n';
//	}
	for(i = 0; i< n; ++i)
		if(L[i][s[i] -'a' + 1] == D[i][s[i] - 'a' + 1] && max < L[i][s[i] - 'a'])
			max = L[i][s[i] - 'a'];

	fout << max * 2 + 1 << '\n';
	return 0;
}