program bing;
const
 max=1000;
var
 f1,f2:text;
 m,n,min,s:integer;
 a:array[1..11,1..11] of integer;
procedure init;
var
 i,j:integer;
begin
 assign(f1,'number.in');reset(F1);
 assign(f2,'number.out');rewrite(F2);
 readln(f1,m,n);
 fillchar(a,sizeof(a),0);
 for i:=1 to m do
 for j:=1 to n do read(f1,a[i,j]);
 min:=max;
 s:=a[1,1];
end;
procedure nb(x,y:integer);
var
 i,j:integer;
begin
 if (x<=m)and(y<=n) then
 begin
 if (x=m)and(y=n) then
  begin if (s<min)and(s>=0) then min:=s;end
 else
 for i:=1 to 2 do
 begin

 if i=1 then begin s:=s+a[x,y+1];nb(x,y+1);s:=s-a[x,y+1];end;
 if i=2 then begin s:=s+a[x+1,y];nb(x+1,y);s:=s-a[x+1,y];end;
 end;
 end;
end;
begin
 init;
 nb(1,1);
 if min=max then write(f2,-1) else write(f2,min);
 close(f1);close(f2);
end.