/Gian - An

              Uses Crt,math;
        Var m,n,i,j:longint;
                a:array[0..1000,0..1000] of longint;
        Begin
            readln(m,n);
            for i:=1 to m do for j:=1 to n do read(a[i,j]);
            for i:=1 to m do
                for j:=1 to n do
                        a[i,j]:=a[i,j]+max(a[i-1,j],a[i,j-1]);
            writeln(a[m,n]);
            readln;
        End.