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>
#include <stdlib.h>
#include <math.h>
#include <string.h>
#define ll long long
#define rep(i,n) for(ll i=0;i<(n);i++)
#define max(p,q) ((p)>(q)?(p):(q))
#define min(p,q) ((p)<(q)?(p):(q))
#define chmax(a,b) ((a)=(a)>(b)?(a):(b))
#define chmin(a,b) ((a)=(a)<(b)?(a):(b))
#define abs(p) ((p)>=(0)?(p):(-(p)))
#define MOD 1000000007
ll powll(ll a,ll b){ll r=1;rep(i,b){r*=a;}return r;}
#define swap(a,b) do{ll w=(a);(a)=(b);(b)=w;}while(0)
#define swapd(a,b) do{double w=(a);(a)=(b);(b)=w}while(0)
#define in(a) scanf("%lld", &(a))
#define in2(a,b) scanf("%lld %lld",&(a),&(b))
#define in3(a,b,c) scanf("%lld %lld %lld",&(a),&(b),&(c))
#define ind(a) scanf("%lf", &(a))
#define ins(a) scanf("%s", (a))
#define inc(a) scanf("%c", &(a))
#define put(a) printf("%lld\n", (a))
#define putd(a) printf("%.15f\n", (a))
//      puts(a) printf("%s\n", a) 文字はこっち
//your code here!
int main(void){
    ll N;
    char s[105], t[105];
    in(N); ins(s); ins(t);
    ll ans=N;
    rep(i, N){
        if(strncmp(s+i, t, N-i)) ans++;
        else break;
    }
    put(ans);
    return 0;
}