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 F first
#define S second
#define MP make_pair
#define pb push_back
#define endl '\n'

using namespace std;

typedef long long LL;
typedef pair< int, int > P;
typedef pair< LL, LL > LP;
typedef pair< int, P > iP;
typedef pair< P, P > PP;

static const int INF = INT_MAX;
static const LL LINF = LLONG_MAX;
static const int MIN = INT_MIN;
static const LL LMIN = LLONG_MIN;
static const int MOD = 1000000007;

int dx[] = {0, -1, 1, 0};
int dy[] = {-1, 0, 0, 1};

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    
    int n;
    string s, t;
    cin >> n >> s >> t;
    int ans = -1;
    for( int i = 0; i < n; ++i ) {
        if( s[i] == t[0] ) {
            bool flg = true;
            for( int j = i + 1; j < n; ++j ) {
                if( s[j] != t[j - i] ) {
                    flg = false;
                    break;
                }
            }
            if( flg ) {
                ans = max( ans, n - i );
            }
        }
    }

    if( ans == -1 ) cout << n * 2 << endl;
    else cout << n * 2 - ans << endl;
    return 0;
}