ll@N,M,x,y,S=1e18;double s,t,p,q,e=1e-18;vector<tuple<ll,ll,int>>A(N),B,C;VVI a(N-1,VI(2)),b=a;rep(i,N){auto&[a,b,j]=A[i];rd(a,b);j=i+1;}auto f=[&](ll u,ll v){auto&[a,b,i]=C[u];auto&[c,d,j]=C[v];a=(a+c)/2;b=(b+d)/2;C.erase(C.begin()+v);};auto m=[&](ll i){p=abs(get<0>(C[i])-5e17),q=abs(get<1>(C[i])-5e17);return max(p,q);};rep(70){e*=2;M=N;B=A;REP(c,M-1){s=1e18**e*M;rep(u,M)rep(v,u+1,M){C=B;f(u,v);t=sum[i,0,M](m(i)**e);if(s>t)s=t,x=u,y=v;}b[c]={get<2>(B[x]),get<2>(B[y])};C=B;f(x,y);B=C;M--;}if(S>m(0))S=m(0),a=b;}wt(N-1);REP(c,N-1)wt(a[c](2));