USACO1.1.4

/*
ID:gwj11391
LANG:C++
TASK:beads
*/
#include<iostream>
#include<algorithm>
#include<string>
#include<fstream>
using namespace std;
int main(){
	ifstream fin("beads.in");
	ofstream fout("beads.out");
	int n, ans = -1;
	string s;
	fin>>n>>s;
	s += s;	s += s;
	for(int i = n; i < s.size(); i++){
		int j1 = i-1, j2 = i, j3, sum = 0;
		while(++j1 < s.size() && s[j1] == s[i] || s[j1] == 'w') sum++;
		while(--j2 >= 0 && s[j2] == 'w') sum++;	j3 = j2;
		while(--j3 >= 0 && s[j3] == s[j2] || s[j3] == 'w') sum++;
		ans = max(ans, sum);
	}
	ans>n? fout<<n<<"
": fout<<ans+1<<"
";
	return 0;
}