In Berland each high school student is characterized by academic performance — integer value between 1 and 5.

In high school 0xFF there are two groups of pupils: the group A and the group B. Each group consists of exactly n students. An academic performance of each student is known — integer value between 1 and 5.

The school director wants to redistribute students between groups so that each of the two groups has the same number of students whose academic performance is equal to 1, the same number of students whose academic performance is 2 and so on. In other words, the purpose of the school director is to change the composition of groups, so that for each value of academic performance the numbers of students in both groups are equal.

To achieve this, there is a plan to produce a series of exchanges of students between groups. During the single exchange the director selects one student from the class A and one student of class B. After that, they both change their groups.

Print the least number of exchanges, in order to achieve the desired equal numbers of students for each academic performance.

Input

The first line of the input contains integer number n (1 ≤ n ≤ 100) — number of students in both groups.

The second line contains sequence of integer numbers a1, a2, ..., an (1 ≤ ai ≤ 5), where ai is academic performance of the i-th student of the group A.

The third line contains sequence of integer numbers b1, b2, ..., bn (1 ≤ bi ≤ 5), where bi is academic performance of the i-th student of the group B.

Output

Print the required minimum number of exchanges or -1, if the desired distribution of students can not be obtained.

Examples

Input

4
5 4 4 4
5 5 4 5


Output

1


Input

6
1 1 1 1 1 1
5 5 5 5 5 5


Output

3


Input

1
5
3


Output

-1


Input

9
3 2 5 5 2 3 3 3 2
4 1 4 1 1 2 4 4 1


Output

4
import java.io.*;
import java.math.BigInteger;
import java.util.*;
 
 
 
 public class Main {
	public static InputReader in;
    public static PrintWriter pw;
 
 
 
	public static void main(String args[]) {
		new Thread(null, new Runnable() {
            public void run() {
                try{
                    solve();
                }
                catch(Exception e){
                    e.printStackTrace();
                }
            }
        }, "1", 1 << 26).start();
    }
	static ArrayList<Pair> g[];
	static ArrayList<Integer> h[];
	static boolean visited[];
	static boolean visit[];
	static int par[];
	static int degree[];
	static int edjes=0;
	static int start=-1;
	static int end=-1;
	static int Total=0;
	static int time1[];
	static int time2[];
	static int glob=0;
	static int ans[];
	static boolean vis2[][];
	//static long sum1=0;
	//static long val[];
    static ArrayList<Integer> levels[];
    static int max=0;
    static int lev=1;
    static ArrayList<Integer> nodes[];
    static ArrayList<Integer> values[];
    static int depth[];
    static boolean found=false;
    static long sm[];
    static int sum1=0;
    static int pre[][];
    
   static  int mn=1000001;
    static Stack<Integer> tt=new Stack();
    public static void solve(){
		
	
		 in = new InputReader(System.in);
		 pw = new PrintWriter(System.out);
         int n=in.nextInt();
         int a[]=in.nextIntArray(n);
         int b[]=in.nextIntArray(n);
         int fr[]=new int[6];
         int as[]=new int[6];
         int bs[]=new int[6];
         for(int i=0;i<n;i++)
         {
        	 fr[a[i]]++;
        	 as[a[i]]++;
         }
         for(int i=0;i<n;i++)
         {
        	 fr[b[i]]++;
        	 bs[b[i]]++;
         }
         
         for(int i=1;i<=5;i++)
         {
        	 if(fr[i]%2!=0)
        	 {
        		 System.out.println(-1);
        		 System.exit(0);
        	 }
        	 //nd[i]=(fr[i]/2);
         }
        int cnt=0;
         for(int i=1;i<=5;i++)
         {
        	 if(as[i]>(fr[i]/2))
        	 {
        		 cnt+=(as[i]-(fr[i]/2));
        	 }
         }
         System.out.println(cnt);
    }

    

	public static int countNumber(int n)
    {
        int result = 0;
     
        // Pushing 1 to 9 because all number from 1
        // to 9 have this propert.
        for (int i = 1; i <= 9; i++)
        {
            Stack<Integer> s=new Stack();
            if (i <= n)
            {
                s.push(i);
                result++;
            }
     
            // take a number from stack and add
            // a digit smaller than last digit
            // of it.
            while (!s.empty())
            {
                int tp = s.peek();
                s.pop();
                for (int j = tp%10; j <= 9; j++)
                {
                    int x = tp*10 + j;
                 //   System.out.println(x);
                    if (x <= n)
                    {
                        s.push(x);
                        result++;
                    }
                }
              //  System.out.println();
            }
        }
     
        return result;
    }
    public static boolean IsPrime(long l) {
		// Corner cases
		if (l <= 1)
			return false;
		if (l <= 3)
			return true;
 
		// This is checked so that we can skip 
		// middle five numbers in below loop
		if (l % 2 == 0 || l % 3 == 0)
			return false;
 
		for (long i = 5; i * i <= l; i = i + 6)
			if (l % i == 0 || l % (i + 2) == 0)
				return false;
 
		return true;
	}
 
     
        
     
        

   
/*public static void dfs2(int curr,int lev)
{
	time1[curr]=glob++;
	
	depth[curr]=lev;
	visited[curr]=true;
	nodes[lev].add(time1[curr]);
	values[lev].add(a[curr]);
	for(int x:g[curr])
	{
		if(!visited[x])
		{
			dfs2(x,lev+1);
		}
	}
time2[curr]=glob++;
}
 
 
 
public static void bfs1(int curr)
{
Queue<Integer> Q=new LinkedList<Integer>();
Q.add(1);
visit[1]=true;
int lev=2;
levels[1].add(1);
while(!Q.isEmpty())
{
	int cnt=Q.size();
	while(cnt>0)
	{
		int p=Q.poll();
		visit[p]=true;
		for(int x:g[p])
		{
			if(!visit[x])
			{
				Q.add(x);
				levels[lev].add(x);
			}
		}
		cnt--;
	}
	max=Math.max(lev, max);
	lev++;
}
}
 
 
	
 	private static long fact(int len) {
	long ans=1;
	for(int i=1;i<=len;i++)
		ans*=i;
	return ans;
}
 
 
 
	
	// SubTree Checker DFS (TO CHECK IF X IS IN A SUBTREE OF Y)
	public static void dfs3(int curr)
	{
		visited[curr]=true;
		time1[curr]=glob++;
		for(int x:g[curr])
		{
		if(!visited[x])
			dfs3(x);
		}
		time2[curr]=glob++;
	}
    
	
	
 
    /*NO OF EDJES IN WHOLE CONNECTED COMPONENTS
  
	public static void dfs1(int curr)
	{
		visited[curr]=true;
		for(int next:g[curr])
		{
			edje++;
			if(!visited[next])
				dfs1(next);
		}
	}
	/*SUM OF ALL SUBTREE NODE'S VLAUES DFS
	public static void dfs(int curr,int prev)
		{
		val[curr]=1;
			for(int x:g[curr])
			{
				if(x!=prev)
				{
		            dfs(x,curr);
		            val[curr]+=val[x];
					
			    }
			}
		}*/
	
		public static long power(long a,long b)
		{
			long result=1;
			while(b>0)
			{
				if(b%2==1)
					result*=a;
				a=a*a;
				b/=2;
			}
			return result;
		}
				public static long pow(long n,long p,long m)
	{
		 long  result = 1;
		  if(p==0)
		    return 1;
		if (p==1)
		    return n;
		while(p!=0)
		{
		    if(p%2==1)
		        result *= n;
		    if(result>=m)
		    result%=m;
		    p >>=1;
		    n*=n;
		    if(n>=m)
		    n%=m;
		}
		return result;
	}
	static class Pair implements Comparable<Pair>{
	int dist;
		int fuel;
		Pair(int ver,int weight){
	     	this.dist=ver;
			this.fuel=weight;
			
		}
		@Override
		public int compareTo(Pair o) {
		//	if(o.finish<this.finish)
		  //  return 1;
		//	else
			return 1;
		}
	}
	public static long gcd(long a, long b) {
		  if (b == 0) return a;
		  return gcd(b, a%b);
		}
	static class InputReader {
 
		private InputStream stream;
		private byte[] buf = new byte[8192];
		private int curChar, snumChars;
		private SpaceCharFilter filter;
 
		public InputReader(InputStream stream) {
			this.stream = stream;
		}
 
		public int snext() {
			if (snumChars == -1)
				throw new InputMismatchException();
			if (curChar >= snumChars) {
				curChar = 0;
				try {
					snumChars = stream.read(buf);
				} catch (IOException e) {
					throw new InputMismatchException();
				}
				if (snumChars <= 0)
					return -1;
			}
			return buf[curChar++];
		}
 
		public   int nextInt() {
			int c = snext();
			while (isSpaceChar(c))
				c = snext();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = snext();
			}
			int res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = snext();
			} while (!isSpaceChar(c));
			return res * sgn;
		}
 
		public long nextLong() {
			int c = snext();
			while (isSpaceChar(c))
				c = snext();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = snext();
			}
			long res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = snext();
			} while (!isSpaceChar(c));
			return res * sgn;
		}
 
		public int[] nextIntArray(int n) {
			int a[] = new int[n];
			for (int i = 0; i < n; i++)
				a[i] = nextInt();
			return a;
		}
 
		public String readString() {
			int c = snext();
			while (isSpaceChar(c))
				c = snext();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = snext();
			} while (!isSpaceChar(c));
			return res.toString();
		}
 
		public boolean isSpaceChar(int c) {
			if (filter != null)
				return filter.isSpaceChar(c);
			return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
		}
 
		public interface SpaceCharFilter {
			public boolean isSpaceChar(int ch);
		}
	}
}
