#include<bits/stdc++.h>
using namespace std;
int n,a,b,ma,b1,b2;
char sc,ec,c[710];
int main()
{
	cin>>n;
	for(int i=1;i<=n;i++)
	{
		cin>>c[i];
		c[i+n]=c[i];
	}
	for(int i=1;i<=n;i++)
	{
		sc=c[i],ec=c[i+n-1];
		a=b=b1=b2=0;
		for(int s=i,e=n+i-1;s<=e;s++,e--)
		{
			if((sc==c[s]||c[s]=='w')&&b1==0)
				a++;
			else
				b1=1;
			if((ec==c[e]||c[e]=='w')&&b2==0)
				b++;
			else
				b2=1;
		}
		ma=max(ma,a+b);
	}
	cout<<ma;
	return 0;
}