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:- module ho4.
:- interface.
:- import_module io.

:- pred main(io__state::di, io__state::uo) is det.

:- implementation.
:- import_module list.

main -->
    {
        p(1)
    ->
        S1 = ""
    ;
        S1 = "\\+ "
    },
    {
        p(2)
    ->
        S2 = ""
    ;
        S2 = "\\+ "
    },
    io__write_strings([S1, "p(1).\n", S2, "p(2).\n"]).

:- pred p(int).
:- mode p(in) is semidet.

p(N) :-
    q(r(5), M),
    M = N.

:- pred q(pred(int), int).
:- mode q(pred(out) is multi, out) is multi.

q(R, N) :-
    R(N).

:- pred r(int, int).
:- mode r(in, out) is multi.

r(A, A).
r(_, 0).