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 5.4.1) (judge verdict: Wrong Answer)

#include <stdio.h>
char a[150], b[150];
int n;
int solve(void) {
  int i;
  if(strncmp(a, b, n) == 0) return n;
  for(i = 0; i < n; i++)
    if(a[n - i - 1] != b[i])
      break;
  return 2 * n - i;
}
int main(void) {
  scanf("%d\n", &n);
  fgets(a, n + 10, stdin);
  fgets(b, n + 10, stdin);
  printf("%d", solve());
  return 0;
}