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 9.2.1) (judge verdict: Accepted)

#include<stdio.h>

int main(){
  int N,ans=0;
  scanf("%d",&N);
  char S[N+1];
  char T[N+1];
  scanf("%s",S);
  scanf("%s",T);

  int i=N-1;
  int j=i;
  while (i>=0)
  {
    int i=N-1;
    while (j>=0&&S[i]!=T[j])
    {
      j--;
    }
    if(j>=0){
      while (j>=0&&S[i]==T[j]){ i--; j--; }
      if (j<0){
        ans=2*N-(N-i-1);
        break;
      }
    }else
    {
      ans=2*N-(N-i-1);
      break;
    }
  }

  printf("%d",ans);

  return 0;
}