/*
ID:gwj11391

LANG:C++

TASK:beads

*/
include
include
include
include
using namespace std;

int main(){

ifstream fin("beads.in");

ofstream fout("beads.out");

int n, ans = -1;

string s;

fin>>n>>s;

s += s; s += s;

for(int i = n; i < s.size(); i++){

int j1 = i-1, j2 = i, j3, sum = 0;

while(++j1 < s.size() && s[j1] == s[i] || s[j1] == 'w') sum++;

while(--j2 >= 0 && s[j2] == 'w') sum++; j3 = j2;

while(--j3 >= 0 && s[j3] == s[j2] || s[j3] == 'w') sum++;

ans = max(ans, sum);

}

ans>n? fout<<n<<"\n": fout<<ans+1<<"\n";

return 0;

}