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: Accepted)

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

int main(){
  int N,cnt=0;
  bool f=true;
  string s,t;
  cin>>N>>s>>t;
  while(f){
    for(int i=0;i<N;i++){
      if(s[s.size()-i-1]!=t[t.size()-i-1]){
        s+=t[t.size()-cnt-1];
        cnt++;
      }
      if(i==N-1) f=false;
    }
  }
  cout<<s.size()<<endl;
}