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>
using namespace std;

int main(){
    int N;
    vector<int> ans;
    string s,t;
    int sl,tl;
    int n;
    bool ire=true;

    cin>>N>>s>>t;
    sl=s.length();
    tl=t.length();
    n=(sl!=tl) ? min(sl,tl) : sl;
    for(int i=0; i<n; i++){
        if(n==tl){
            if(s.substr(sl-n+i,sl)==t.substr(0,n-i)){
                ans.push_back(sl+tl-(n-i));
                ire=false;
            }
        }
        if(n==sl){
            if(s.substr(i,n)==t.substr(0,n-i)){
                ans.push_back(sl+tl-(n-i));
                ire=false;
            }
        }
    }

    for(int i=0; i<ans.size(); i++){
        if(ans[i]>=N){
            cout<<ans[i]<<endl;
            break;
        }
    }
    if(ire){
        cout<<tl+sl<<endl;
    }

    return 0;
}