#include <bits/stdc++.h>
using namespace std;
#define rep(i,N) for(int i=0;i<int(N);++i)
#define rep1(i,N) for(int i=1;i<int(N);++i)
#define all(a) (a).begin(),(a).end()
#define print(v) { cerr<<#v<<": [ "; for(auto _ : v) cerr<<_<<", "; cerr<<"]"<<endl; }
#define printpair(v) { cerr<<#v<<": [ "; for(auto _ : v) cerr<<"{"<<_.first<<","<<_.second<<"}"<<", "; cerr<<"]"<<endl; }
#define dump(x) cerr<<#x<<": "<<x<<endl;
#define bit(k) (1LL<<(k))
typedef long long ll;
typedef pair<int, int> i_i;
typedef pair<ll, ll> l_l;
template <class T> using vec = vector<T>;
template <class T> using vvec = vector<vec<T>>;
template< typename T1, typename T2 >
ostream &operator<<(ostream &os, const pair< T1, T2 >& p) {
  os << "{" <<p.first << ", " << p.second << "}";
  return os;
}
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }

const int INF = (ll)1e9;
const ll INFLL = (ll)1e18+1;
const ll MOD = (ll)1e9+7;
const double PI = acos(-1.0);
/*
const int dx[8] = {1, 0, -1, 0, 1, -1, -1, 1};
const int dy[8] = {0, 1, 0, -1, 1, 1, -1, -1};
const string dir = "DRUL";
*/

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(20);
    int N;
    cin >> N;
    string s, t;
    cin >> s >> t;
    string ans = s + t;
    for(int i = 1; i <= N; i++){
        if(s.substr(N-i,i) == t.substr(0,i)){
            ans = s + t.substr(i, N-i);
        }
    }
    cout << ans.size() << endl;
}

#include <bits/stdc++.h>
using namespace std;
int main() {
    long long int N;
    string s,t;
    cin>>N>>s>>t;
    long long len1,len2,count=0;
    len1=s.length();
    len2=t.length();
if(len1==len2&&len1==N&&N>=1&&N<=100){
 if (N>=len1+len2){
        count=N;
 }
else {
    count=len1+len2;
        for(int i=0;i<=len1;i++){
            for(int j=1;j<=len2;j++){
                if(s.substr(i,len1)==t.substr(0,j)&&len1+len2-j>=N){
                    count=min(len1+len2-j,count);
                }
            }
        }
}
cout<<count;
}
    return 0;
}