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>
#include <stdlib.h>
#include <string.h>
int main() {
    char a[101], b[101];
    int n, i, j, cnt=0;
    scanf("%d\n", &n);
    gets(a);
    gets(b);
    for(i=n-1, j=0;i>=0 && j<n;i--, j++) {
        if(a[i]!=b[j]) break;
        else cnt++;
    }
    //printf("i:%d, j:%d\n", i, j);
    cnt+=i+1;
    cnt+=n-j;
    printf("%d", cnt);
    return 0;
}