#include <bits/stdc++.h>
#if __has_include(<atcoder/all>)
#include <atcoder/all>
using namespace atcoder;
#endif
using namespace std;

#define ll long long
#define rep(i, n) for (ll i = 0; i < n; ++i)
#define rep_up(i, a, n) for (ll i = a; i < n; ++i)
#define rep_down(i, a, n) for (ll i = a; i >= n; --i)
#define P pair<ll, ll>
#define pb push_back
#define bit_count(x) __builtin_popcountll(x)
#define gcd(a,b) __gcd(a,b)
#define lcm(a,b) a / gcd(a,b) * b
#define all(v) v.begin(), v.end()

int main(){
    ll n;
    string s;
    cin>>n;
    cin>>s;
    assert(1<=n&&n<=300000);
    assert(n==s.size());
    rep(i,n){
        assert(s[i]=='#'||s[i]=='.');
    }
    reverse(all(s));
    ll ans=-1000000000;
    rep(i,n){
        if(s[i]=='#'){
            ans=max(ans+2,i+1);
        }
    }
    cout<<ans<<endl;
}