#include <iostream>
#include <algorithm>
#include <iomanip>
#include <vector>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <tuple>
#include <cmath>
#include <numeric>
#include <functional>
#include <cassert>

#define debug_value(x) cerr << "line" << __LINE__ << ":<" << __func__ << ">:" << #x << "=" << x << endl;
#define debug(x) cerr << "line" << __LINE__ << ":<" << __func__ << ">:" << x << endl;

template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }

using namespace std;
typedef long long ll;

template<typename T>
vector<vector<T>> vec2d(int n, int m, T v){
    return vector<vector<T>>(n, vector<T>(m, v));
}

template<typename T>
vector<vector<vector<T>>> vec3d(int n, int m, int k, T v){
    return vector<vector<vector<T>>>(n, vector<vector<T>>(m, vector<T>(k, v)));
}

template<typename T>
void print_vector(vector<T> v, char delimiter=' '){
    if(v.empty()) {
        cout << endl;
        return;
    }
    for(int i = 0; i+1 < v.size(); i++) cout << v[i] << delimiter;
    cout << v.back() << endl;
}

using P = pair<int, int>;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << setprecision(10) << fixed;
    auto f = vec2d(500, 500, -1);
    for(int i = 0; i < 500; i++) {
        for(int j = 0; j < 500; j++) {
            int ii = i/9;
            f[i][j] = (i%9)*9 + (j%10 + (ii%2 == 0 ? 0 : 5))%10;
        }
    }
    vector<vector<int>> points(90);
    int n; cin >> n;
    for(int i = 0; i < n; i++){
        int x, y; cin >> x >> y; x--; y--;
        points[f[x][y]].push_back(i);
    }
    for(int a = 0; a < 90; a++){
        if(points[a].size()*90 >= n){
            cout << points[a].size() << "\n";
            for(auto i: points[a]) cout << i+1 << ' ';
            cout << endl;
        }
        return 0;
    }
}