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 PHP (5.6.30) (judge verdict: Wrong Answer)

#include <bits/stdc++.h>
using namespace std;

#define dump(x)  cout << #x << " = " << (x) << endl;

typedef long long ll;
typedef pair<int, int> ii;
const int mod = 1e9+7;
const ll INF = 1e18;
const int inf = 1e9;

void solve()
{
  int n;cin>>n;
  string s,t;
  cin>>s>>t;

  int p=0;
  for (int i=0; i<=n; i++) {
    if (s.substr(n-i,i) == t.substr(0,i)) {
      p = i;
    }
  }
  cout << 2*n-p << endl;
}

int main()
{
  solve();
  return 0;
}