USACO 1.1-beads

/*
ID: m1590291
PROG: beads 
LANG: C++
*/
#include <iostream>
#include <fstream>

using namespace std;

int main()
{
	int num,max=0,n,i,j,k;
	char *p,symbol1,symbol2;
	ifstream fin("beads.in");
	ofstream fout("beads.out");
 
	fin>>n;
	p=new char[n+1];
	fin>>p;
 
	for(i=n;i<2*n;++i){
		if(p[i%n]!=p[(i+1)%n]){                               
			symbol1=p[i%n]!='w'?p[i%n]:(p[(i+1)%n]=='r'?'b':'r');   
			symbol2=symbol1=='r'?'b':'r';
			num=0;
 
			for(j=i;j>i-n;--j){
				if(p[j%n]==symbol1||p[j%n]=='w') ++num;        
				else break;
			}
			for(k=i+1;k<j+n+1;++k){
				if(p[k%n]==symbol2||p[k%n]=='w') ++num;
				else break;
			}
 
			max=max>num?max:num;                     
		}
	}
 
	if(max==0) max=n;                               
	fout<<max<<endl;
	fin.close();
	fout.close();
	delete [] p;
 
	return 0;
}