#include <iostream>
#include <vector>
using namespace std;

bool isLeap(int year) {
    if (year % 4 != 0) return false;
    else if (year % 100 != 0) return true;
    else return (year % 400 == 0);
}

int main() {
    int x, y;
    cin >> x >> y;
    vector<int> leapYears;
    
    for (int year = x; year <= y; ++year) {
        if (isLeap(year)) {
            leapYears.push_back(year);
        }
    }
    
    cout << leapYears.size() << endl;
    for (int i = 0; i < leapYears.size(); ++i) {
        if (i != 0) cout << " ";
        cout << leapYears[i];
    }
    cout << endl;
    
    return 0;
}```