//#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
#define rep(i, n) for(int i=0; i<n; ++i)
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
using namespace std;
using ll = int64_t;
using ld = long double;
using P = pair<int, int>;
using vs = vector<string>;
using vi = vector<int>;
using vvi = vector<vi>;
template<class T> using PQ = priority_queue<T>;
template<class T> using PQG = priority_queue<T, vector<T>, greater<T> >;
const int INF = 0xccccccc;
const ll LINF = 0xcccccccccccccccLL;
template<typename T1, typename T2>
inline bool chmax(T1 &a, T2 b) {return a < b && (a = b, true);}
template<typename T1, typename T2>
inline bool chmin(T1 &a, T2 b) {return a > b && (a = b, true);}
template<typename T1, typename T2>
istream &operator>>(istream &is, pair<T1, T2> &p) { return is >> p.first >> p.second;}
template<typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) { return os << p.first << ' ' << p.second;}



//head

vvi uu(90);
int num(int i, int j) {return j >= 9 ? num((i+5)%10, j-9) : i*9+j;}

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	int n;
	cin >> n;
	rep(i, n) {
		int x, y;
		cin >> x >> y;
		x %= 10;
		y %= 18;
		uu[num(x, y)].push_back(i+1);
	}
	rep(i, 90) {
		if(uu[i].size() >= (n+89)/90) {
			cout << uu[i].size() << endl;
			rep(j, uu[i].size()) {
				if(j) cout << ' ';
				cout << uu[i][j];
			}
			cout << endl;
			return 0;
		}
	}
}