program number;
Type
fxz=array[1..10,1..10] of longint;
var
f1,f2:text;
i,j,m,n,min:longint;
f:boolean;
a:fxz;
procedure sc(i,j:integer;ls:longint);
begin
ls:=ls+a[i,j];
if (i=m)and(j=n) then if (ls<=min)and(ls>0) then begin min:=ls;f:=true;end;
if i<>m then sc(i+1,j,ls);
if j<>n then sc(i,j+1,ls);
end;
begin
assign(f1,'number.in');
assign(f2,'number.out');
reset(f1);rewrite(f2);
readln(f1,m,n);
for i:=1 to m do
begin
for j:=1 to n do
read(f1,a[i,j]);
readln(f1);
end;
f:=false;min:=32757;
{.........................................}
sc(1,1,0);
if f then writeln(f2,min)
     else writeln(f2,'-1');
close(f1);close(f2);
end.