program cl;
const Maxn = 10;
var a : array[1..Maxn,1..Maxn]of integer;
    b : array[1..Maxn]of integer;
    i,j,n : integer;
    min : integer;
    nach,kon : integer;
    nnew : array[1..Maxn]of boolean;

procedure PG(k : integer;v : integer;lmin : integer);
var i : integer;
    lm : integer;
begin
   nnew[v] := true;
   if k > 0 then lm := (b[v] + k - 1) div k else lm := maxint;
   if lm < lmin then lmin := lm;
   if v = kon then
      begin
         if lmin > min then min := lmin;
      end else
         for i := 1 to n do
            if (a[v,i] > 0) and (not nnew[i]) then
               PG(k + 1,i,lmin);
   nnew[v] := false;
end;

begin
   fillchar(nnew,sizeof(nnew),false);
   assign(input,'cl_resh.in');reset(input);
   readln(n);
   for i := 1 to n do
      for j := 1 to n do
         read(a[i,j]);
   for i := 1 to n do
      read(b[i]);
   readln(nach,kon);
   min := 0;
   PG(0,nach,maxint);
   writeln(min);
end.