program EmberAsh;
var
a:array[1..20000,1..10]of longint;
f:array[1..2000000]of longint;
i,j,k,m,n,max,head:longint;

procedure try(x,y,s:longint);
var
i,j,k,x1,y1,s1:longint;
begin
if (x=m)and(y=n) then
  begin
  inc(head);
  f[head]:=s;
  end
    else
    begin
    if y+1<=n then//left
      begin
      x1:=x;
      y1:=y+1;
      s1:=s+a[x1,y1];
      try(x,y+1,s1);
      end;
    if x+1<=m then//down
      begin
      x1:=x+1;
      y1:=y;
      s1:=s+a[x1,y1];
      try(x+1,y,s1);
      end;
    end;
end;

BEGIN
assign(input,'number.in');reset(input);
assign(output,'number.out');rewrite(output);
readln(m,n);
for i:=1 to m do
  for j:=1 to n do
    read(a[i,j]);
try(1,1,0);
max:=maxlongint;
for i:=1 to head do
  if (f[i]>0)and(f[i]<max) then
    max:=f[i];
if max=maxlongint then
  writeln(-1)
  else
  writeln(max);
close(input);close(output);
END.