Problem:
Score : 200 points

Problem Statement

Snuke is interested in strings that satisfy the following conditions:

The length of the string is at least N.

The first N characters equal to the string s.

The last N characters equal to the string t.

Find the length of the shortest string that satisfies the conditions.

Constraints

1≤N≤100

The lengths of s and t are both N.

s and t consist of lowercase English letters.

Input

The input is given from Standard Input in the following format:

N
s
t

Output

Print the length of the shortest string that satisfies the conditions.

Sample Input 1

3
abc
cde

Sample Output 1

5

The shortest string is abcde.

Sample Input 2

1
a
z

Sample Output 2

2

The shortest string is az.

Sample Input 3

4
expr
expr

Sample Output 3

4

The shortest string is expr.

Solution in C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <set>
#include <map>
#include <queue>
#include<limits.h>
#include<iomanip>
#define rep(i, n) for(int i = 0; i < n; i++)
#define REP(i, m, n) for(int i = m; i < n; i++)
#define ALL(v) v.begin(),v.end()
#define RALL(v) v.rbegin(),v.rend()
#define check(v) rep(i,v.size()) cout << v[i] << " ";\
cout << endl
#define INF 1e8
typedef long long ll;
using namespace std;
//オーバーフローに気をつけろよおおおおおお
//確認忘れるなよおおおおおお

int main() {
    int n; cin >> n;
    string a, b; cin >> a >> b;
    int ans = 0;
    reverse(ALL(b));
    rep(i,n){
        if(a[i]==b[i]) ans++;
        else ans+=2;
    }
    cout << max(n,ans) << endl;

    return 0;
}