program uspon;
var n,v,i,j,p: integer;
    a: array[1..1000] of integer;
    u: boolean;
begin
 readln (n);
 for i:=1 to n do begin
        read(a[i]);
 end;
 v:=0; p:=0; u:=false;
 for i:=1 to n do begin
        if a[i+1]>a[i] then begin
             u:=true;
             p:=p+(a[i+1]-a[i]);
             if p>v then v:=p;
        end
        else begin
             u:=false;
             p:=0;
        end;
 end;
 writeln (v);
end.