#include <bits/stdc++.h>
using namespace std;
using ch = char;
using ll = long long;
using ld = long double;
using db = double;
using st = string;
using vdb = vector<db>;
using vvdb = vector<vdb>;
using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vd = vector<ld>;
using vvd = vector<vd>;
using vs = vector<st>;
using vvs = vector<vs>;
using vc = vector<ch>;
using vvc = vector<vc>;
using vb = vector<bool>;
using vvb = vector<vb>;
using vvvb = vector<vvb>;
const ll mod = 998244353;
const ll MOD = 1000000007;
using vp = vector<pair<ll,ll>>;
#define fi first
#define se second

int main(){
  ll N;
  cin>>N;
  st S;
  cin>>S;
  ll a;
  bool f=true;
  for(int i=N-1; i>-1; i--){
    if(S.at(i)=='#'){
      if(f){
        a=N-i;
        f=false;
      }
      else{
        a=max(N-i,a+2);
      }
    }
  }
  cout<<a<<endl;
}