#include <bits/stdc++.h>   using namespace std;   int main() {     int n, k;     cin >> n;     string s;     cin >> s;     int l = s.length(), ct = 1;     for (int i = 1; i < l; i++) {       if (s[i] != s[i - 1]) ct++;     }     if (ct >= (n - 1))       cout << n;     else       cout << ct + 2;     return 0;   }   