#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<int, int>;
const long long INF = 1001001001;
const long long MOD = 1000000007;
const double EPS = 1e-10;

P cmp[505][505];
P rev[505][505];

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);

    ll n;
    cin>>n;
    int x[n],y[n];
    P xy[n];
    P p1[n],p2[n];
    for(int i=0;i<n;i++){
        cin>>x[i]>>y[i];
        xy[i]=P(x[i],y[i]);
        p1[i]=P(x[i],y[i]);
        p2[i]=P(y[i],x[i]);
    }
    sort(p1,p1+n);
    sort(p2,p2+n);
    int maxx=0,maxy=0;
    for(int i=0,prex=-1,curv=-1;i<n;i++){
        if(prex!=p1[i].first)curv++;
        cmp[p1[i].first][p1[i].second].first=curv;
        maxx=max(maxx,curv);
        prex=p1[i].first;
    }
    for(int i=0,prey=-1,curv=-1;i<n;i++){
        if(prey!=p2[i].first)curv++;
        cmp[p2[i].second][p2[i].first].second=curv;
        maxy=max(maxy,curv);
        prey=p2[i].first;
    }
    for(int i=0;i<n;i++){
        rev[cmp[x[i]][y[i]].first][cmp[x[i]][y[i]].second]=P(x[i],y[i]);
    }
    vector<P> vec;
    for(int i=0;i<=maxx;i+=10){
        for(int j=0;j<=maxy;j+=10){
            vec.emplace_back(rev[cmp[j][i].first][cmp[j][i].second]);
        }
    }
    if(vec.size()<n/90){
        for(;;);
    }
    cout<<vec.size()<<endl;
    for(auto aeiou:vec){
        int idx=lower_bound(xy,xy+n,aeiou)-xy;
        cout<<idx+1<<endl;
    }
}