#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

map<pll, int> sv;
map<int, pll> inv;
void point(ll y, ll x, ll t) {
    if (sv.count({y, x}))
        sv.erase({y, x});
    else
        sv[{y, x}] = t;
}

int main() {
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif

    ios_base::sync_with_stdio(0);
    cin.tie(0);

    ll a, b;
    cin >> a >> b;

    ll p = 1, q = 1;
    while (p * q < b) {
        if (p == q)
            p++;
        else
            q++;
    }
    ll x = 0, y = 1e9;
    if (a % 2 == 0 && 2 * (p + q) <= a && a <= 2 * (b + 1)) {
        ll k[p], s = 2 * (p + q);
        for (int i = 0; i < p; i++) {
            k[i] = min(q, b);
            b -= k[i];
        }
        ll m = k[0], r = 0;
        point(0, 0, x++);
        point(0, 1, x++);
        point(k[0], 0, y--);
        point(k[0], 1, y--);
        for (int i = 1; i < p; i++) {
            if (2 * (k[i] - 1) + s <= a) {
                s += 2 * (k[i] - 1);
                m += k[i];
            } else {
                r++;
                m += (a - s) / 2;
                s = a;
            }
            point(m, r, y--);
            point(m, r + 1, y--);
            point(m - k[i], r, x++);
            point(m - k[i], r + 1, x++);
        }
        cout << sv.size() << "\n";
        for (auto u : sv) inv[u.second] = u.first;
        for (auto u : inv) cout << u.second.first << " " << u.second.second << "\n";
    } else
        cout << -1;
}