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.IOException;
    import java.io.InputStream;
    import java.io.PrintWriter;
    import java.io.*;
    import java.util.*;
    import java.util.LinkedList;
    import java.math.*;
    import java.lang.*;
    import java.util.PriorityQueue;
    import static java.lang.Math.*;
    @SuppressWarnings("unchecked")
    public class Solution implements Runnable {
        static class InputReader {
            private InputStream stream;
            private byte[] buf = new byte[1024];
            private int curChar;
            private int numChars;
            private SpaceCharFilter filter;
            private BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

            public InputReader(InputStream stream) {
                this.stream = stream;
            }

            public int read() {
                if (numChars==-1)
                    throw new InputMismatchException();

                if (curChar >= numChars) {
                    curChar = 0;
                    try {
                        numChars = stream.read(buf);
                    }
                    catch (IOException e) {
                        throw new InputMismatchException();
                    }

                    if(numChars <= 0)
                        return -1;
                }
                return buf[curChar++];
            }

            public String nextLine() {
                String str = "";
                try {
                    str = br.readLine();
                }
                catch (IOException e) {
                    e.printStackTrace();
                }
                return str;
            }
            public int nextInt() {
                int c = read();

                while(isSpaceChar(c))
                    c = read();

                int sgn = 1;

                if (c == '-') {
                    sgn = -1;
                    c = read();
                }

                int res = 0;
                do {
                    if(c<'0'||c>'9')
                        throw new InputMismatchException();
                    res *= 10;
                    res += c - '0';
                    c = read();
                }
                while (!isSpaceChar(c));

                return res * sgn;
            }

            public long nextLong() {
                int c = read();
                while (isSpaceChar(c))
                    c = read();
                int sgn = 1;
                if (c == '-') {
                    sgn = -1;
                    c = read();
                }
                long res = 0;

                do {
                    if (c < '0' || c > '9')
                        throw new InputMismatchException();
                    res *= 10;
                    res += c - '0';
                    c = read();
                }
                while (!isSpaceChar(c));
                    return res * sgn;
            }

            public double nextDouble() {
                int c = read();
                while (isSpaceChar(c))
                    c = read();
                int sgn = 1;
                if (c == '-') {
                    sgn = -1;
                    c = read();
                }
                double res = 0;
                while (!isSpaceChar(c) && c != '.') {
                    if (c == 'e' || c == 'E')
                        return res * Math.pow(10, nextInt());
                    if (c < '0' || c > '9')
                        throw new InputMismatchException();
                    res *= 10;
                    res += c - '0';
                    c = read();
                }
                if (c == '.') {
                    c = read();
                    double m = 1;
                    while (!isSpaceChar(c)) {
                        if (c == 'e' || c == 'E')
                            return res * Math.pow(10, nextInt());
                        if (c < '0' || c > '9')
                            throw new InputMismatchException();
                        m /= 10;
                        res += (c - '0') * m;
                        c = read();
                    }
                }
                return res * sgn;
            }

            public String readString() {
                int c = read();
                while (isSpaceChar(c))
                    c = read();
                StringBuilder res = new StringBuilder();
                do {
                    res.appendCodePoint(c);
                    c = read();
                }
                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 String next() {
                return readString();
            }

            public interface SpaceCharFilter {
                public boolean isSpaceChar(int ch);
            }
        }
        public static long min(long a,long b)
        {
            if(a>b)
            {
                return b;
            }
            return a;
        }
        public static int min(int a,int b)
        {
            if(a>b)
            {
                return b;
            }
            return a;
        }
        public static long max(long a,long b)
        {
            if(a>b)
            {
                return a;
            }
            return b;
        }
        public static int max(int a,int b)
        {
            if(a>b)
            {
                return a;
            }
            return b;
        }
        static class pair implements Comparable<pair>
        {
          int x;
          int y;
          pair(int x,int y)
          {
            this.x = x;
            this.y = y;
          }
          public int compareTo(pair b)
          {
            if(this.x>b.x)
            {
              return 1;
            }
            else if(this.x<b.x)
            {
              return -1;
            }
            else
            {
              return this.y-b.y;
            }
          }
        }
        public static int gcd(int a,int b)
        {
            if(a==0)
            return b;
            if(b==0)
            return a;
            while((a%=b)!=0&&(b%=a)!=0);
            return a^b;
        }
        public static int mod(int a)
        {
          if(a>0)
            return a;
          return -a;
        }
        static int mod = (int)1e9+7;;
        public static long expo(long exp,long pow)
        {
          long ans = 1;
          while(pow!=0)
          {
            if((pow&1)==1)
            {
              ans = ans*exp;
            }
            exp = exp*exp;
            pow = pow>>1;
          }
          return ans;
        }
        static int max = (int)1e6;
        public static long fact(int num)
        {
            if(num==0)
            {
              return 1;
            }
            return (fact(num-1)*num)%mod;
        }
        static int[] sieve;
        public static void sieve()
        {
          sieve = new int[max+1];
          for(int i=1;i<=max;i++)
          {
            sieve[i] = i;
          }
          for(int i=2;i<max;i++)
          {
            if(sieve[i]==i)
            {
              for(int j=i*2;j<=max;j+=i)
              {
                if(sieve[j]==j)
                {
                  sieve[j] = i;
                }
              }
            }
          }
        }
        public static int random(int min,int max)
        {
          return (int)((max-min)*Math.random());
        }
        public static void main(String args[]) throws Exception {
            new Thread(null, new Solution(),"Main",1<<26).start();
        }
        public void run() {
          InputReader sc  = new InputReader(System.in);
          PrintWriter out = new PrintWriter(System.out);
          int t1 = 1;
          while(t1-->0)
          {
            int n = sc.nextInt();
            int[] a = new int[n];
            int[] b = new int[n];
            int[] count1 = new int[6];
            int[] count2 = new int[6];
            for(int i=0;i<n;i++)
            {
              a[i] = sc.nextInt();
              count1[a[i]]++;
            }
            for(int i=0;i<n;i++)
            {
              b[i] = sc.nextInt();
              count2[b[i]]++;
            }
            int ans = 0;
            for(int i=1;i<=5;i++)
            {
              int diff = count2[i]-count1[i];
              if(diff<0)
              {
                diff = -diff;
                if((diff&1)==1)
                {
                  ans = -1;
                  break;
                }
                continue;
              }
              if((diff&1)==1)
              {
                ans = -1;
                break;
              }
              ans+=diff/2;
            }
            out.println(ans);
          }
          out.close();
         }
    }
