#include<bits/stdc++.h>
using namespace std;
string s1,s2;
int main()
{
int n,ans=0,maxx=-1;cin>>n;
cin>>s1;
for (int i=1;i<=n;++i) s2[i]=s1[i-1];
for (int i=1;i<=n;++i)
{
ans=0;
int left=i,right=i+1;
while(left!=i+1&&(s2[left]==s2[i]||(s2[left]=='w')))
{
if (left==0) left=n;
--left;
++ans;
}
while (right!=i&&(s2[right]==s2[i+1]||s2[right]=='w'))
{
if (right==n) right=0;
++right;
++ans;
}
maxx=max(ans,maxx);
}
cout<<maxx;
return 0;
}