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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include<iostream>
#include<iomanip>
#include<iterator>
#include<list>
#include<math.h>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<string>
#include<set>
#include<vector>
#include<map>
#include<unordered_map>
#include<queue>
#include<utility>
#include<numeric>
#include<functional> 
#define sz(a) int((a).size()) 
#define pb push_back 
#define eb emplace_back
#define mp make_pair
#define mt make_tuple
#define ld(a) while(a--)
#define tci(v,i) for(auto i=v.begin();i<v.end();i++)
#define tcf(v,i) for(auto i : v)
#define all(v) v.begin(),v.end()
#define rep(i,start,lim) for(long long (i)=(start);i<(lim);i++)
#define repd(i,start,lim) for(long long (i)=(start);i>=(lim);i--)
#define cpresent(c,x) (find(all(c),x) != (c).end())
#define sync ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define osit ostream_iterator
#define MOD 		1000000007
#define INF 		0x3f3f3f3f
#define LLINF       1000111000111000111LL
#define pi 			3.14159265358979323
#define endl '\n'
#ifdef WIN32
#define getchar_unlocked getchar
#endif
#define gc getchar
#define trace1(x)                cerr<<#x<<": "<<x<<endl
#define trace2(x, y)             cerr<<#x<<": "<<x<<" | "<<#y<<": "<<y<<endl
#define trace3(x, y, z)          cerr<<#x<<":" <<x<<" | "<<#y<<": "<<y<<" | "<<#z<<": "<<z<<endl
#define trace4(a, b, c, d)       cerr<<#a<<": "<<a<<" | "<<#b<<": "<<b<<" | "<<#c<<": "<<c<<" | "<<#d<<": "<<d<<endl
#define trace5(a, b, c, d, e)    cerr<<#a<<": "<<a<<" | "<<#b<<": "<<b<<" | "<<#c<<": "<<c<<" | "<<#d<<": "<<d<<" | "<<#e<< ": "<<e<<endl
#define trace6(a, b, c, d, e, f) cerr<<#a<<": "<<a<<" | "<<#b<<": "<<b<<" | "<<#c<<": "<<c<<" | "<<#d<<": "<<d<<" | "<<#e<< ": "<<e<<" | "<<#f<<": "<<f<<endl
#define N 1000006
using namespace std;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef long long int ll;
typedef vector<long long int> vll;
typedef vector<vll> vvll;
typedef long double ld;
typedef pair<int,int> ii;
typedef vector<ii> vii;
typedef vector<vii> vvii;
typedef tuple<int,int,int> iii;
typedef set<int> si;
typedef priority_queue<ii,vii,greater<ii> > spq;
template<typename T> T gcd(T a,T b){if(a==0) return b; return gcd(b%a,a);}
template<typename T>void read(T &x) { register T c = gc(); x = 0; int t = 0; if (c == '-') t = 1, c = gc(); for (; (c < 48 || c>57); c = gc()); for (; c > 47 && c < 58; c = gc()) { x = (x << 1) + (x << 3) + c - 48; }if (t) x = -x; }
template<typename T> T pow(T x,T y){T ans=1;while(y>0){if(y%2==1) ans=(ans*x)%MOD;y/=2;x=(x*x)%MOD;}return ans;} //using this instead of inbuilt pow due to precision issues in that
template<typename T> ll roundp(T x){ll ans=x;if(x-floor(x)<=0.001) ans=floor(x);else if(ceil(x)-x<=0.001) ans=ceil(x);return ans;}
int main(){
	int n; cin>>n; string s,t; cin>>s>>t;
	ll ans,ct=0;
	for(int i=0;i<n;i++){
		ct=0; ll dct=0;
		for(int j=i;j<n;j++,dct++){
			if(s[j]==t[dct]) ++ct;
			else {
			ct=0;break;	
			}
		}
		if(ct!=0) break;
	}
	//trace1(ct);
	cout<<(ct+2*(n-ct))<<endl;
}