#include<bits/stdc++.h>
using namespace std;
#define REP(i,m,n) for(int i=(int)(m) ; i < (int) (n) ; ++i )
#define rep(i,n) REP(i,0,n)
typedef long long ll;

ll gcd(ll x,ll y){
	if(x<y)swap(x,y);
	return y? gcd(y,x%y) : x;
}

int main(){
	ll a,b,c,d;
	cin>>a>>b>>c>>d;
	ll ret=abs(a*d-b*c);
	cout<<ret<<endl;
	ll g=gcd(a,c);
	rep(i,g)rep(j,ret/g){
		cout<<i<<" "<<j<<endl;
	}
	return 0;
}