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
/*
Logic is the strongest weapon.
 */


import java.io.*;
import java.math.*;
import java.util.*;
import java.util.Map.Entry;

public class Coding {

    private static InputStream stream;
    private static byte[] buf = new byte[1024];
    private static int curChar;
    private static int numChars;
    private static SpaceCharFilter filter;
    private static PrintWriter pw;
    private static int N = 1234567;

    public static int soln() {
        int n = nI();
        int[] a = new int[5];
        int[] b = new int[5];
        for (int i = 0; i < n; i++) {
            a[nI() - 1]++;
        }
        for (int i = 0; i < n; i++) {
            b[nI() - 1]++;
        }
        int ra = 0, rb = 0;
        int[] c = new int[5];
        for (int i = 0; i < 5; i++) {
            int t = a[i] + b[i];
            if (t % 2 == 1) {
                pw.println(-1);
                return 0;
            }
            t /= 2;
            c[i] = a[i] - t;
            if (c[i] < 0) {
                ra -= c[i];
            }
            if (c[i] > 0) {
                rb += c[i];
            }
        }
        pw.println(Math.max(ra, rb));
        return 0;
    }

    public static void main(String[] args) {
        InputReader(System.in);
        pw = new PrintWriter(System.out);
        soln();
        pw.close();
    }

    /*
     *********************************************************************************************
     */
    public static void InputReader(InputStream stream1) {
        stream = stream1;
    }

    private static boolean isWhitespace(int c) {
        return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    }

    private static boolean isEndOfLine(int c) {
        return c == '\n' || c == '\r' || c == -1;
    }

    private static 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++];
    }

    private static int nI() {
        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;
    }

    private static long nL() {
        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;
    }

    private static String nS() {
        int c = read();
        while (isSpaceChar(c)) {
            c = read();
        }
        StringBuilder res = new StringBuilder();
        do {
            res.appendCodePoint(c);
            c = read();
        } while (!isSpaceChar(c));
        return res.toString();
    }

    private static String nLi() {
        int c = read();
        while (isSpaceChar(c)) {
            c = read();
        }
        StringBuilder res = new StringBuilder();
        do {
            res.appendCodePoint(c);
            c = read();
        } while (!isEndOfLine(c));
        return res.toString();
    }

    private static boolean isSpaceChar(int c) {
        if (filter != null) {
            return filter.isSpaceChar(c);
        }
        return isWhitespace(c);
    }

    private interface SpaceCharFilter {

        public boolean isSpaceChar(int ch);
    }
}
