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: Accepted)

#include<stdio.h>
void input(int *N, char *s, char *t)
{
    scanf("%d", N);
    scanf("%s", s);
    scanf("%s", t);
}
int str_slide_compare(char *str1, char *str2, int num)
{
    for (int i = 0; i < num; i++){
        if(str1[i] != str2[i]){
            return 0;
        }
    }
    return 1;
}
int main(void)
{
    char s[101];
    char t[101];
    int N;

    input(&N, s, t);

    int slide;
    for (slide = 0; slide <= 100; slide++){
        if (str_slide_compare(s + slide, t, N - slide)) {
            break;
        }
    }
    printf("%d\n",slide+N);
}