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++ (GCC 9.2.1) (judge verdict: Accepted)

#include <iostream>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
using namespace std;
#define rep(i, a, b) for(int i = a; i<b; i++)
int main() {
    int n;
    string s, t;
    cin >> n >> s >> t;
    rep(i, 0, n) {
      string s2 = s.substr(i, n - i);
      string t2 = t.substr(0, n - i);
      if(s2 != t2) continue;
      cout << n + i << endl;
      return 0;
    }
    cout << n * 2 << endl;
}