program cch(input,output);
const
 xx:array[1..2] of integer=(1,0);
 yy:array[1..2] of integer=(0,1);
var
 i,j,m,n,ans,ch:integer;
 a:array[1..10,1..10] of integer;

procedure search(x,y:integer);
var
 i,x1,y1:integer;
begin
 if (x=m)and(y=n) then
  begin
   if (ch>0)and(ch<ans) then ans:=ch;
   exit;
  end;
 for i:=1 to 2 do
  begin
   x1:=x+xx[i]; y1:=y+yy[i];
   if (x1>=1)and(x1<=m)and(y1>=1)and(y1<=n) then
    begin
     ch:=ch+a[x1,y1];
     search(x1,y1);
     ch:=ch-a[x1,y1];
    end;
  end;
end;

begin
 assign(input,'number.in');
 assign(output,'number.out');
 reset(input);
 rewrite(output);
 readln(m,n);
 for i:=1 to m do
  for j:=1 to n do
   read(a[i,j]);
 ans:=maxint;
 ch:=a[1,1];
 search(1,1);
 if ans=maxint then write(-1)
               else write(ans);
 close(input);
 close(output);
end.