#include<bits/stdc++.h >
using namespace std;

int x,y,s=0,m[10001]; 
bool rn(int a){
	bool f=1;
	if(a%100!=0){
		if(a%4!=0){
			f=0;
		}
	}
	else{
		if(a%400!=0){
			f=0;
		} 
	}
	return f;
}

int main(){
	//freopen("fenyou.in","r",stdin);
    //freopen("fenyou.out","w",stdout);
	cin>>x>>y;
	for(int i=x;i<=y;i++){
		if(rn(i)){
			s++;
			m[s]=i;
		}
	}
	cout<<s<<endl;
	for(int i=1;i<=s;i++){
		cout<<m[i]<<" ";
	}
}