LINEGAME PASCAL

var n:longint;
    a,f,g:array[0..1000000] of longint;
    t,i:longint;
function max(a,b:longint):longint;
var x:longint;
begin
    x:=a;
    if b>x then x:=b;
    exit(x);
end;

procedure nhap;
var i:longint;
begin
    read(n);
    for i:=1 to n do read(a[i]);
end;

procedure giai;
begin
    f[0]:=0;g[0]:=0;
    for i:=1 to n do
    begin
        f[i]:=max(f[i-1],g[i-1]+a[i]);
        g[i]:=max(g[i-1],f[i-1]-a[i]);
    end;
    writeln(max(f[n],g[n]));
end;
begin
   assign(input,'linegame.inp');reset(input);
   assign(output,'linegame.out');rewrite(output);
   nhap;
   giai;

   close(input);close(output);
end.