program number;
var
  table:array [1..10,1..10] of integer;
  min,i,j,m,n:integer;
procedure go(x,y,sum:integer);
begin
  if (x=1) and (y=1) then begin
    if (sum>0) and (sum<min) then min:=sum;
  end
  else begin
    if x-1>=1 then go(x-1,y,sum+table[x,y]);
    if y-1>=1 then go(x,y-1,sum+table[x,y]);
  end;
end;
begin
  assign (input,'number.in');
  reset (input);
  readln (m,n);
  min:=maxint;
  for i:=1 to m do for j:=1 to n do read (table[i,j]);
  close (input);
  assign (output,'number.out');
  rewrite (output);
  go(m,n,0);
  if min=maxint then min:=-1;
  writeln (min);
  close (output);
end.