#include<map>

 #include<cstdio>

 #include<algorithm>

 #define rep(i,l,r) for (int i=(l); i<=(r); i++)

 #define For(i,x) for (int i=h[x],k; i; i=nxt[i])

 using namespace std;

 const int N=,M=,inf=;

 bool va[N],vb[N];

 int n,mx,cnt=,s0,ss,tt,S,T,d[N],f[N],h[N],dis[N],idx[N],q[N],cur[N],a[N],mp[N][];

 int Lst[N],Nxt[N],pre[N],suf[N],premx[N],sufmx[N],to[M],fl[M],nxt[M],Do[N],Do2[N];

 struct P{ int x,y; }p[N];

 bool cmp1(int a,int b){ return (p[a].y==p[b].y) ? p[a].x<p[b].x : p[a].y<p[b].y; }

 bool cmp2(int a,int b){ return (p[a].x==p[b].x) ? p[a].y<p[b].y : p[a].x<p[b].x; }

 bool cmp3(int a,int b){ return (p[a].x-p[a].y==p[b].x-p[b].y) ? p[a].y<p[b].y : p[a].x-p[a].y<p[b].x-p[b].y; }

 bool cmp4(int a,int b){ return (p[a].x+p[a].y==p[b].x+p[b].y) ? p[a].y<p[b].y : p[a].x+p[a].y<p[b].x+p[b].y; }

 bool cmp5(int a,int b){ return (p[a].y==p[b].y) ? p[a].x<p[b].x : p[a].y>p[b].y; }

 inline void add(int u,int v,int w){

     to[++cnt]=v; fl[cnt]=w; nxt[cnt]=h[u]; h[u]=cnt;

     to[++cnt]=u; fl[cnt]=; nxt[cnt]=h[v]; h[v]=cnt;

 }

 void work(int u,int v,int low,int high){ add(u,v,high-low); d[u]-=low; d[v]+=low; }

 bool bfs(){

     rep(i,,n+) dis[i]=; dis[S]=; q[]=S;

     for (int st=,ed=; st<ed; ){

         int x=q[++st];

         For(i,x) if (fl[i] && !dis[k=to[i]]) dis[k]=dis[x]+,q[++ed]=k;

     }

     return dis[T];

 }

 int dfs(int x,int lim){

     if (x==T) return lim;

     int c=;

     for (int i=cur[x],k; i; i=nxt[i])

         if (fl[i] && dis[k=to[i]]==dis[x]+){

             int t=dfs(k,min(lim-c,fl[i]));

             c+=t; fl[i]-=t; fl[i^]+=t;

             if (fl[i]) cur[x]=i;

             if (c==lim) return lim;

         }

     if (!c) dis[x]=-;

     return c;

 }

 int dinic(){

     int res=;

     while (bfs()){

         rep(i,,n+) cur[i]=h[i];

         res+=dfs(S,inf);

     }

     return res;

 }

 void Print(int x){

     if (!x) return;

     printf("%d ",x);

     if (Do[x]==) { Print(mp[x][Do2[x]]); return; }

     if (idx[x]>idx[Do[x]]){

         int t=Do[x];

         for (int i=Nxt[x]; i; i=Nxt[i]) printf("%d ",i);

         for (x=Lst[x]; x!=t; x=Lst[x]) printf("%d ",x);

         printf("%d ",t); Print(mp[t][Do2[t]]); return;

     }

     if (idx[x]<idx[Do[x]]){

         int t=Do[x];

         for (int i=Lst[x]; i; i=Lst[i]) printf("%d ",i);

         for (x=Nxt[x]; x!=t; x=Nxt[x]) printf("%d ",x);

         printf("%d ",t); Print(mp[t][Do2[t]]); return;

     }

 }

 void solve1(){

     rep(i,,n) a[i]=i;

     sort(a+,a+n+,cmp1);

     rep(i,,n) if (p[a[i-]].y==p[a[i]].y) Lst[a[i]]=a[i-],Nxt[a[i-]]=a[i];

     sort(a+,a+n+,cmp2);

     rep(i,,n) if (p[a[i-]].x==p[a[i]].x) mp[a[i-]][]=a[i];

     sort(a+,a+n+,cmp3);

     rep(i,,n) if (p[a[i-]].x-p[a[i-]].y==p[a[i]].x-p[a[i]].y) mp[a[i-]][]=a[i];

     sort(a+,a+n+,cmp4);

     rep(i,,n) if (p[a[i-]].x+p[a[i-]].y==p[a[i]].x+p[a[i]].y) mp[a[i-]][]=a[i];

     sort(a+,a+n+,cmp5);

     rep(i,,n) idx[a[i]]=i;

 }

 void W(int x){

     rep(i,,) if (mp[x][i]){

         int to=mp[x][i];

         if (f[to]+>f[x]) Do2[x]=i,f[x]=f[to]+;

     }

 }

 int calc(int x,int y){

     return (idx[x]<idx[y]) ? pre[y]+f[mp[y][Do2[y]]] : suf[y]+f[mp[y][Do2[y]]];

 }

 bool jud(P &p){ return p.x== || p.x==p.y || p.x==-p.y; }

 void solve2(){

     rep(k,,n) if (p[a[k]].y!=p[a[k-]].y) pre[a[k]]=; else pre[a[k]]=pre[a[k-]]+;

     for (int k=n; k; k--) if (p[a[k]].y!=p[a[k+]].y) suf[a[k]]=; else suf[a[k]]=suf[a[k+]]+;

     rep(k,,n) if (p[a[k]].y!=p[a[k-]].y){

         for (int x=a[k]; x; x=Nxt[x]) f[x]=,W(x);

         for (int x=a[k]; x; x=Nxt[x])

             for (int y=a[k]; y; y=Nxt[y])

                 if (y!=x && calc(x,y)>f[x]) f[x]=calc(x,y),Do[x]=y;

     }

     rep(i,,n) if (jud(p[i])) mx=max(mx,f[i]);

     printf("%d\n",mx);

     rep(i,,n) if (f[i]==mx && jud(p[i])) { Print(i); break; }

     puts("");

 }

 int solve3(){

     rep(i,,n) if (f[i]==mx && jud(p[i])) work(s0,i,,inf),va[i]=;

     for (int i=n; i; i--) if (p[a[i]].y!=p[a[i+]].y){

         for (int x=a[i]; x; x=Lst[x]) if (va[x]){

             if (f[mp[x][Do2[x]]]+==f[x]) vb[x]=;

             for (int y=a[i]; y; y=Lst[y]) if (y!=x && calc(x,y)==f[x]) vb[y]=;

         }

         for (int x=a[i]; x; x=Lst[x])

             if (vb[x]) rep(j,,) if (mp[x][j] && f[mp[x][j]]==f[mp[x][Do2[x]]])

                 va[mp[x][j]]=,work(x,mp[x][j],,inf);

     }

     rep(i,,n+) work(ss,i,,inf),work(i,tt,,inf);

     rep(i,,n+) if (d[i]>) add(S,i,d[i]); else add(i,T,-d[i]);

     add(tt,ss,inf); dinic(); S=tt; T=ss; return inf-dinic();

 }

 int main(){

     freopen("driver.in","r",stdin);

     freopen("driver.out","w",stdout);

     scanf("%d",&n); s0=n+; ss=n+; tt=n+; S=n+; T=n+;

     rep(i,,n) scanf("%d%d",&p[i].x,&p[i].y);

     solve1(); solve2(); printf("%d\n",solve3());

     return ;

 }