In a kindergarten, the children are being divided into groups. The teacher put the children in a line and associated each child with his or her integer charisma value. Each child should go to exactly one group. Each group should be a nonempty segment of consecutive children of a line. A group's sociability is the maximum difference of charisma of two children in the group (in particular, if the group consists of one child, its sociability equals a zero). 

The teacher wants to divide the children into some number of groups in such way that the total sociability of the groups is maximum. Help him find this value.

Input

The first line contains integer n — the number of children in the line (1 ≤ n ≤ 106).

The second line contains n integers ai — the charisma of the i-th child ( - 109 ≤ ai ≤ 109).

Output

Print the maximum possible total sociability of all groups.

Examples

Input

5
1 2 3 1 2


Output

3


Input

3
3 3 3


Output

0

Note

In the first test sample one of the possible variants of an division is following: the first three children form a group with sociability 2, and the two remaining children form a group with sociability 1.

In the second test sample any division leads to the same result, the sociability will be equal to 0 in each group.
/**
 * Created by Aminul on 8/9/2018.
 */

import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.InputMismatchException;
import static java.lang.Math.*;

public class CF484D_3 {
    public static void main(String[] args)throws Exception {
        FastReader in = new FastReader(System.in);
        PrintWriter pw = new PrintWriter(System.out);

        int n = in.nextInt();
        boolean [] bad = new boolean[n+1];
        int [] arr = new int[n+2];
        for (int i = 1; i <= n; i++) {
            arr[i] = in.nextInt();
        }


        int [] prevBad = new int[n+1];
        bad[1] = bad[n] = true;
        for (int i = 2; i < n; i++) {
            if ((arr[i] >= arr[i-1] && arr[i] >= arr[i+1]) || (arr[i] < arr[i-1] && arr[i] <= arr[i+1])) {
                bad[i] = bad[i-1] = bad[i+1] = true;
            }
            if(bad[i-1]) prevBad[i] = i-1;
            else prevBad[i] = prevBad[i-1];
        }

        long dp[] = new long[n+1];
        for (int i = 1; i <= n; i++) {
            dp[i] = dp[i-1];
            long min = arr[i], max = arr[i];
            for(int j = i-1, k = 1; k <= 10 && j >= 1; j = prevBad[j], k++){
                min = min(min, arr[j]);
                max = max(max, arr[j]);
                dp[i] = max(dp[i], dp[j-1] + max - min);
            }
        }

        pw.println(dp[n]);

        pw.close();
    }

    static void debug(Object...obj) {
        System.err.println(Arrays.deepToString(obj));
    }

    static class FastReader {
        InputStream is;
        private byte[] inbuf = new byte[1024];
        private int lenbuf = 0, ptrbuf = 0;
        static final int ints[] = new int[128];

        public FastReader(InputStream is){
            for(int i='0';i<='9';i++) ints[i]=i-'0';
            this.is = is;
        }

        public int readByte(){
            if(lenbuf == -1)throw new InputMismatchException();
            if(ptrbuf >= lenbuf){
                ptrbuf = 0;
                try { lenbuf = is.read(inbuf); } catch (IOException e) { throw new InputMismatchException(); }
                if(lenbuf <= 0)return -1;
            }
            return inbuf[ptrbuf++];
        }

        public boolean isSpaceChar(int c) {
            return !(c >= 33 && c <= 126);
        }
        public int skip() {
            int b;
            while((b = readByte()) != -1 && isSpaceChar(b));
            return b;
        }

        public String next(){
            int b = skip();
            StringBuilder sb = new StringBuilder();
            while(!(isSpaceChar(b))){ // when nextLine, (isSpaceChar(b) && b != ' ')
                sb.appendCodePoint(b);
                b = readByte();
            }
            return sb.toString();
        }

        public int nextInt(){
            int num = 0, b;
            boolean minus = false;
            while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
            if(b == '-'){
                minus = true;
                b = readByte();
            }

            while(true){
                if(b >= '0' && b <= '9'){
                    num = (num<<3) + (num<<1) + ints[b];
                }else{
                    return minus ? -num : num;
                }
                b = readByte();
            }
        }

        public long nextLong() {
            long num = 0;
            int b;
            boolean minus = false;
            while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
            if(b == '-'){
                minus = true;
                b = readByte();
            }

            while(true){
                if(b >= '0' && b <= '9'){
                    num = (num<<3) + (num<<1) + ints[b];
                }else{
                    return minus ? -num : num;
                }
                b = readByte();
            }
        }

        public double nextDouble() {
            return Double.parseDouble(next());
        }
       /* public char nextChar() {
            return (char)skip();
        }*/

        public char[] next(int n){
            char[] buf = new char[n];
            int b = skip(), p = 0;
            while(p < n && !(isSpaceChar(b))){
                buf[p++] = (char)b;
                b = readByte();
            }
            return n == p ? buf : Arrays.copyOf(buf, p);
        }

        /*private char buff[] = new char[1005];
        public char[] nextCharArray(){
            int b = skip(), p = 0;
            while(!(isSpaceChar(b))){
                buff[p++] = (char)b;
                b = readByte();
            }
            return Arrays.copyOf(buff, p);
        }*/
    }
}