#include "reachin1000".

source(3).

% Way 1
reach(X) :- source(X).
reach(Y) :- edge(X,Y), reach(X).
% Way 2
%reach(Y) :- edge(X,Y), reach(X).
%reach(X) :- source(X).
% Way 3
%reach(X) :- source(X).
%reach(Y) :- reach(X), edge(X,Y).
% Way 4
%reach(Y) :- reach(X), edge(X,Y).
%reach(X) :- source(X).