#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

struct HopcroftKarp {
    static const int N = 2e5 + 10;
    vector<int> adj_left[N];
    int matchL[N] = {};
    int matchR[N] = {};
    int root[N], prev[N], qq[N];

    void add_edge(int u, int v) {
        adj_left[u].push_back(v);
    }
    void init(int L, int R) {
        for (int i = 1; i <= L; i++) {
            adj_left[i].clear();
            matchL[i] = 0;
        }
        for (int i = 1; i <= R; i++) {
            matchR[i] = 0;
        }
    }
    void init_matching(int L, int R) {
        for (int i = 1; i <= L; i++) {
            matchL[i] = 0;
        }
        for (int i = 1; i <= R; i++) {
            matchR[i] = 0;
        }
    }
    int maxmatching(int L, int R) {
        int sz = 0;
        for (bool updated = true; updated; ) {
            updated = false;
            for (int i = 1; i <= L; i++) {
                root[i] = -1;
                prev[i] = -1;
                qq[i] = 0;
            }
            int qi = 0, qj = 0;
            for (int i = 1; i <= L; i++) {
                if (matchL[i] == 0) {
                    qq[qj++] = i, root[i] = i, prev[i] = i;
                }
            }
            while (qi < qj) {
                int u = qq[qi++];
                if (matchL[root[u]] != 0) {
                    continue;
                }
                for (int v : adj_left[u]) {
                    if (matchR[v] == 0) {
                        while (v != 0) {
                            matchR[v] = u, swap(matchL[u], v), u = prev[u];
                        }
                        updated = true;
                        sz++;
                        break;
                    }
                    if (prev[matchR[v]] == -1) {
                        v = matchR[v], prev[v] = u, root[v] = root[u], qq[qj++] = v;
                    }
                }
            }
        }
        return sz;
    }
};

HopcroftKarp hk;

struct Kek {
    int l, r, id;
    bool operator<(const Kek& ot) const{
        return tie(r, l, id) < tie(ot.r, ot.l, ot.id);
    }
};

const int inf = 1e9;
const int N = 2e5 + 10;
int mn[N], mx[N];
Kek a[N];

int f(int x, int mod) {
    return ((x % mod) + mod) % mod;
}

vector<pair<int, int>> solve(int n, int m) {
    for (int i = 2; i <= n + m; i++) {
        mn[i] = inf;
        mx[i] = -inf;
    }
    for (int i = 1; i <= n; i++) {
        for (int j : {1, m}) {
            mn[i + j] = min(mn[i + j], i - j);
            mx[i + j] = max(mx[i + j], i - j);
        }
    }
    for (int j = 1; j <= m; j++) {
        for (int i : {1, n}) {
            mn[i + j] = min(mn[i + j], i - j);
            mx[i + j] = max(mx[i + j], i - j);
        }
    }
    for (int i = 2; i <= n + m; i++) {
        a[i] = {mn[i], mx[i], i};
    }
    sort(a + 2, a + n + m + 1);
    set<int> s[2];
    for (int i = 1 - m; i <= n - 1; i++) {
        s[f(i, 2)].insert(i);
    }
    vector<pair<int, int>> ans;
    for (int i = 2; i <= n + m; i++) {
        int t = a[i].id & 1;
        auto it = s[t].lower_bound(a[i].l);
        if (it != s[t].end() && *it <= a[i].r) {
            int sum = a[i].id;
            int dif = *it;
            int x = (sum + dif) / 2;
            int y = (sum - dif) / 2;
            ans.emplace_back(x, y);
            s[t].erase(it);
        }
    }
    return ans;
}

int slow(int n, int m) {
    hk.init(n + m, n - 1 + m);
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            hk.add_edge(i + j, i - j + m);
        }
    }
    return hk.maxmatching(n + m, n - 1 + m);
}

bool check(const vector<pair<int, int>>& vec) {
    set<int> sum, dif;
    for (auto [i, j] : vec) {
        if (sum.count(i + j)) {
            return false;
        }
        if (dif.count(i - j)) {
            return false;
        }
        sum.insert(i + j);
        dif.insert(i - j);
    }
    return true;
}

void stress() {
    mt19937 rnd;
    while (true) {
        int n = rnd() % 30 + 1;
        int m = rnd() % 30 + 1;
        auto ans = solve(n, m);
        int res = slow(n, m);
        if (ans.size() == res && check(ans)) {
            cout << "OK" << endl;
        } else {
            cout << "WA\n";
            cout << n << " " << m << "\n";
            cout << ans.size() << " " << res << "\n";
            break;
        }
    }
    exit(0);
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
#ifdef LOCAL
    freopen("input.txt", "r", stdin);
#endif

    // stress();

    int n, m;
    cin >> n >> m;
    auto ans = solve(n, m);
    cout << ans.size() << "\n";
    for (auto [i, j] : ans) {
        cout << i << " " << j << "\n";
    }
    // assert(check(ans));

#ifdef LOCAL
    cout << "\nTime elapsed: " << double(clock()) / CLOCKS_PER_SEC << " s.\n";
#endif
}