program xmz;
var
x:array[1..10,1..10]of integer;
i,j,s,m,n,t:integer;
f1,f2:text;
procedure nn(a,b:integer);
begin
s:=s+x[a,b];
if a<m then
  nn(a+1,b);
if b<n then
  nn(a,b+1);
if (a=m)and(b=n)then
 if s>0 then
  if s<t then
   t:=s;
s:=s-x[a,b];
end;

begin
assign(f1,'number.in');assign(f2,'number.out');
reset(f1);rewrite(f2);
t:=maxint;
read(f1,m,n);
for i:=1 to m do
 for j:=1 to n do
  read(f1,x[i,j]);
nn(1,1);
if t<>maxint then
write(f2,t)
else write(f2,-1);

close(f1);close(f2);
end.