#define _CRT_SECURE_NO_WARNINGS
#define _SCL_SECURE_NO_WARNINGS
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cassert>
#include <iostream>
#include <string>
#include <vector>
#include <list>
#include <utility>
#include <algorithm>
#include <functional>
#include <cmath>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <iomanip>
#include <sstream>
#include <bitset>
#include <limits>
#include <numeric>
#include <valarray>
#include <fstream>

using namespace std;
typedef unsigned int uint;
typedef long long LL;
typedef unsigned long long ULL;
typedef pair<LL, LL> PP;
#define REP(i, a, n) for(LL i = (a), i##_max = (n); i < i##_max; ++i)
#define REM(i, a, n) for(LL i = (LL)(n) - 1, i##min = (a); i >= i##min; --i)
#define ALL(arr) (arr).begin(), (arr).end()
#define FLOAT fixed << setprecision(16)
#define SPEEDUP {cin.tie(NULL); ios::sync_with_stdio(false);}
const int INF = 0x3FFFFFFF;
const LL INFLL = 0x3FFFFFFF3FFFFFFF;
const double INFD = 1.0e+308;
const double EPS = 1.0e-9;

void YesNo(bool b) { cout << (b ? "Yes" : "No") << endl; }
void YESNO(bool b) { cout << (b ? "YES" : "NO") << endl; }
template <class T, class U>
istream& operator>>(istream& ist, pair<T, U>& right) { return ist >> right.first >> right.second; }
template <class T, class U>
ostream& operator<<(ostream& ost, const pair<T, U>& right) { return ost << right.first << ' ' << right.second; }
template <class T, class TCompatible, size_t N>
void Fill(T(&dest)[N], const TCompatible& val) { fill(dest, dest + N, val); }
template <class T, class TCompatible, size_t M, size_t N>
void Fill(T(&dest)[M][N], const TCompatible& val) { for (int i = 0; i < M; ++i) Fill(dest[i], val); }
template<class T>
T Compare(T left, T right) { return left > right ? 1 : (left < right ? -1 : 0); }
istream& Ignore(istream& ist) { string s; ist >> s; return ist; }
bool Inside(int i, int j, int h, int w) { return i >= 0 && i < h && j >= 0 && j < w; }
template <class T>
T Next() { T buf; cin >> buf; return buf; }

#ifdef ONLY_MY_ENVIR
#include "IntMod.h"
#include "BinaryMatrix.h"
#include "BIT.h"
#include "Factorization.h"
#include "FlowSolver.h"
#include "Graph.h"
#include "LazySegmentTree.h"
#include "Math.h"
#include "Matrix.h"
#include "MinMax.h"
#include "Position.h"
#include "Range.h"
#include "Rational.h"
#include "SegmentTree.h"
#include "SegmentTree2D.h"
#include "SuffixArray.h"
#include "Tree.h"
#include "UnionFind.h"
#include "MinCostFlowSolver.h"
#endif

#ifdef __GNUC__
typedef __int128 LLL;
istream& operator>> (istream& ist, __int128& val) { LL tmp;  ist >> tmp; val = tmp; return ist; }
ostream& operator<< (ostream& ost, __int128 val) { LL tmp = val; ost << tmp; return ost; }
#endif

#if 1234567891
#include <array>
#include <random>
#include <unordered_set>
#include <unordered_map>
template<typename T>
using PriorityQ = priority_queue<T, vector<T>, greater<T> >;
// template <class T>
// auto Is(const T& value) { return [value](const auto& comparand) -> bool { return comparand == value; }; }
#endif

LL D;
vector<PP> even_sub(LL x, LL y) {
	vector<PP> ret;
	if (x < D && y < D) {
		ret.push_back(PP(D, y - D));
		ret.push_back(PP(x, y));
	} else {
		int cx = 0;
		int cy = 0;
		while (y - cy > 2 * D) {
			if (x - cx >= D) cx += D;
			cy += D;
			ret.push_back(PP(cx, cy));
		}

		ret.push_back(PP(x - D, cy + D));
		ret.push_back(PP(x, y));
	}
	return ret;
}

vector<PP> even(LL x, LL y) {
	vector<PP> ret;
	if (x <= y) {
		ret = even_sub(x, y);
	} else {
		auto res = even_sub(y, x);
		for (auto p : res) {
			ret.push_back(PP(p.second, p.first));
		}
	}
	return ret;
}

vector<PP> odd_sub(LL x, LL y) {
	vector<PP> ret;
	if (x < D && y < D) {
		ret.push_back(PP(D, y - D));
		ret.push_back(PP(x, y));
	} else {
		int cx = 0;
		int cy = 0;
		while (y - cy > 2 * D) {
			cx += D;
			cy += D;
			ret.push_back(PP(cx, cy));
			if (x - cx >= 0) {
				cx += D;
			} else {
				cx -= D;
			}
			cy += D;
			ret.push_back(PP(cx, cy));
		}

		if (x - cx >= 0) {
			ret.push_back(PP(x - D, cy + D));
		} else {
			ret.push_back(PP(x + D, cy + D));
		}
		ret.push_back(PP(x, y));
	}
	return ret;
}

vector<PP> odd(LL x, LL y, bool mod) {
	int sgnx = (x >= 0 ? 1 : -1);
	int sgny = (y >= 0 ? 1 : -1);
	x = abs(x);
	y = abs(y);

	vector<PP> ret;
	if (mod) {
		auto res = odd(x - D, y - D, false);

		ret.push_back(PP(D, D));
		for (auto p : res) {
			ret.push_back(PP(p.first + D, p.second + D));
		}
	} else {
		if (x <= y) {
			ret = odd_sub(x, y);
		} else {
			auto res = odd_sub(y, x);
			for (auto p : res) {
				ret.push_back(PP(p.second, p.first));
			}
		}
	}

	for (auto&& p : ret) {
		p.first *= sgnx;
		p.second *= sgny;
	}
	return ret;

}

vector<PP> sub(LL x, LL y, bool is_odd, bool mod) {
	int sgnx = (x >= 0 ? 1 : -1);
	int sgny = (y >= 0 ? 1 : -1);
	x = abs(x);
	y = abs(y);

	vector<PP> ret;
	if (max(x, y) == D) {
		ret.push_back(PP(x, y));
	} else if (is_odd) {
		ret = odd(x, y, mod);
	} else {
		ret = even(x, y);
	}

	for (auto&& p : ret) {
		p.first *= sgnx;
		p.second *= sgny;
	}
	return ret;
}

int main() {
	LL X, Y;
	cin >> D >> X >> Y;
	if (D % 2 == 0 && abs(X + Y) % 2 == 1) {
		cout << -1 << endl;
		return 0;
	}

	LL P = X + Y;
	LL Q = X - Y;
	
	auto ans = sub(P, Q, D % 2 == 1, abs(X + Y) % 2 == 1);
	cout << ans.size() << endl;
	for (PP pi : ans) {
		LL P = pi.first;
		LL Q = pi.second;

		LL X = (P + Q) / 2;
		LL Y = (P - Q) / 2;
		cout << X << ' ' << Y << endl;
	}

	bool ok = true;
	int px = 0, py = 0;
	for (auto pi : ans) {
		LL P = pi.first;
		LL Q = pi.second;

		LL X = (P + Q) / 2;
		LL Y = (P - Q) / 2;
		if (abs(px - X) + abs(py - Y) != D) {
			ok = false;
		}
		px = X;
		py = Y;
	}

	//assert(ok);
	cerr << (ok ? "OK" : "NG") << endl;
	return 0;
}

Measured memory_bytes: 11244