import java.util.*;

public class quadrilha {
    public static void main( String[] args ){
        Scanner s = new Scanner(System.in);
        int n = s.nextInt();
        int ans = 0; 
        for( int i = 0; i < n; i++ ){
            int x = s.nextInt();
            ans += (i%2 == 1) ? x : -x; 
        }
        s.close();
        System.out.println(Math.abs(ans));
    }
}