#include <cstdio>
#include <cstring>
#include <iostream>
#include <string>
#include <cmath>
#include <bitset>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <algorithm>
#include <complex>
#include <unordered_map>
#include <unordered_set>
#include <random>
#include <cassert>
#include <fstream>
#include <utility>
#include <functional>
#include <time.h>
#include <stack>
#include <array>
#define popcount __builtin_popcount
using namespace std;
typedef long long int ll;
typedef pair<int, int> P;
int num[510][504];
int main()
{
	for(int i=0; i<500; i++){
		for(int j=0; j<504; j++){
			if(j/9%2==0){
				int x=i%10, y=j%9;
				num[i][j]=x+y*9;
			}else{
				int x=(i+5)%10, y=j%9;
				num[i][j]=x+y*9;
			}
		}
	}
	int n; cin>>n;
	vector<int> v[90];
	for(int i=0; i<n; i++){
		int x, y; cin>>x>>y;
		x--; y--;
		v[num[x][y]].push_back(i);
	}
	for(int i=0; i<90; i++){
		if(v[i].size()>=(n+89)/90){
			cout<<v[i].size()<<endl;
			for(auto k:v[i]) cout<<k+1<<" ";
			cout<<endl;
			return 0;
		}
	}
	return 0;
}