#include<bits/stdc++.h>
#define ll long long
#define endl '\n'
#define up(i,j,k,l) for(int i=j;i<=k;i+=l)
#define down(i,j,k,l) for(int i=j;i>=k;i-=l)
using namespace std;
const int N=3e2+5e1+10;
int n;
char a[N];
int zd[N],yd[N];
int l,r,res,ans;
void solve()
{
	cin>>n;
	up(i,1,n,1){
		cin>>a[i];
		zd[i]=i-1;
		yd[i]=i+1;
	}
	zd[1]=n;
	yd[n]=1;
	up(i,1,n,1){
		l=zd[i];
		r=i;
		res=0;
		while(1){
			if(l==yd[i]){
				cout<<n;
				return;
			}
			if(a[l]!=a[zd[i]] && a[l]!='w'){
				l=yd[l];
				break;
			}
			else{
				res++;
				l=zd[l];
			}
		}
		while(1){
			if(r==zd[i]){
				cout<<n;
				return;
			}
			if(a[r]!=a[i] && a[r]!='w'){
				r=zd[r];
				break;
			}
			else{
				res++;
				r=yd[r];
			}
		}
		//cout<<l<<' '<<r<<' '<<res<<endl;
		ans=max(ans,res);
	}
	cout<<ans;
	return;
}
int main()
{
    //ios::sync_with_stdio(false);
	//cin.tie(0);
	//freopen(".in","r",stdin);
	//freopen(".out","w",stdout);
	int _=1;
	//cin>>_;
	up(i,1,_,1){
		solve();
	}
	return 0;
}