%%
database( {
	sure(N:string),	
	friend(A:string, B:string)
} ).

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
export willcome(P).

%%
willcome(P)<-sure(P).
willcome(P)<-c_friends(P,K),K>=3.
c_friends(P,mcount<F>)<-willcome(F),friend(P,F).

single(mcount, X, 1).
multi(mcount,  X, Old, New) <- New=Old+1.

return(mcount, X, nil, 1).
return(mcount, X, Old, New)<-Old~=nil, New=Old+1.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
export wllcome(P,C).

%%
wllcome(P,yes)<-sure(P).
wllcome(P,kcount<(3,F)>)<-wllcome(F,yes),friend(P,F).

single(kcount, (K,X), 1).
multi(kcount,  (K,X), Old, New) <- Old<K, New=Old+1.
return(kcount, (K,X), K1, yes)<-K1~=nil, K=K1+1.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
export wllcme(P).

%%
wllcme(P)<-sure(P).
wllcme(P,zcount<(3,F)>)<-wllcme(F),friend(P,F).

single(zcount, (K,X), 1).
multi(zcount,  (K,X), Old, New) <- Old<K, New=Old+1.
return(zcount, (K,X), K1)<-K1~=nil, K=K1+1.