#include <algorithm>
#include <cstring>
typedef long long ll;
using namespace std; 
/* run this program using the console pauser or add your own getch, system("pause") or input loop */
const int N=1e6+5;
int main() {
	int n;
	string s;
	cin>>n>>s;
	int ans1=0,ans2=0,ans=0;
	for(int i=0;i<n;i++){
		char key='o';
		int count=0,j=i;
		while(s[j]=='w'||key=='o'||s[j]==key){
			count++;
			if(key=='o'&&s[j]!='w'){
				key=s[j];
			}
			j=(j+1)%n;
			if(count>=n){
				ans1=n;
				break;
			}
			ans1=count;
		}
		key='o';
		count=0,j=n-i-2;
		while(s[j]=='w'||key=='o'||s[j]==key){
			count++; 
			if(key=='o'&&s[j]!='w'){
				key=s[j];
			}
			j=(j+n-1)%n;
			if(count>=n){
				ans2=n;
				break;
			}
			ans2=count;
		}
		ans=max(ans1+ans2,ans);
	}
	cout<<min(ans,n);
	return 0;
}