//#pragma GCC optimize("Ofast", "unroll-loops")
//#pragma GCC target("sse", "sse2", "sse3", "ssse3", "sse4")
#ifdef LOCAL
#include <iostream>
#include <cmath>
#include <algorithm>
#include <stdio.h>
#include <cstdint>
#include <cstring>
#include <string>
#include <cstdlib>
#include <vector>
#include <bitset>
#include <map>
#include <queue>
#include <ctime>
#include <stack>
#include <set>
#include <list>
#include <random>
#include <deque>
#include <functional>
#include <iomanip>
#include <sstream>
#include <fstream>
#include <complex>
#include <numeric>
#include <cassert>
#include <array>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <thread>
#else
#include <bits/stdc++.h>
#endif

#define all(a) a.begin(),a.end()
#define len(a) (int)(a.size())
#define mp make_pair
#define pb push_back
#define fir first
#define sec second
#define fi first
#define se second

using namespace std;

typedef pair<int, int> pii;
typedef long long ll;
typedef long double ld;

template<typename T>
inline bool umin(T &a, T b) {
    if (b < a) {
        a = b;
        return true;
    }
    return false;
}

template<typename T>
inline bool umax(T &a, T b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}

#ifdef LOCAL
#define D for (bool _FLAG = true; _FLAG; _FLAG = false)
#define LOG(...) print(#__VA_ARGS__" ::", __VA_ARGS__) << endl
template <class ...Ts> auto &print(Ts ...ts) { return ((cerr << ts << " "), ...); }
#else
#define D while (false)
#define LOG(...)
#endif // LOCAL

const int max_n = -1, inf = 1000111222;


vector <pii> ans;

inline int f (int n, int m) {
    int ans = (n + m + (n & 1) + (m & 1) - 1) / 2;
    if (n == m && n % 2) {
        --ans;
    }
    return max(1, ans);
}
inline void solve1 (int n, int m, int x, int y, int sgnx, int sgny);

inline void solve2 (int n, int m, int x, int y, int sgnx, int sgny) {
    LOG(2, n, m);
    if (n % 2 == 0) {
        solve1(n, m, x + (n + 1) * sgnx, y, -sgnx, sgny);
        return;
    }
    else if (m % 2 == 0) {
        solve1(n, m, x, y + (m + 1) * sgny, sgnx, -sgny);
        return;
    }

    if (n == 1) {
        for (int i = 2; i <= m; i += 2) {
            ans.pb({x + 1 * sgnx, y + i * sgny});
        }
        return;
    }
    if (m == 1) {
        for (int i = 2; i <= n; i += 2) {
            ans.pb({x + i * sgnx, y + 1 * sgny});
        }
        return;
    }
//    if (n == m) {
//        if (n >= 2) {
//            for (int i = 1; i <= n; i += 2) {
//                ans.pb({x + sgnx * 2, y + i * sgny});
//            }
//            for (int i = 4; i <= n - 3; i += 2) {
//                ans.pb({x + sgnx * n, y + i * sgny});
//            }
//        }
//        return;
//    }
    if (n < m) {
        for (int i = 2; i <= n; i += 2) {
            ans.pb({x + i * sgnx, y + 1 * sgny});
        }
        solve2(n, m - n + 1, x, y + (n - 1) * sgny, sgnx, sgny);
        return;
    }
    for (int i = 2; i <= m; i += 2) {
        ans.pb({x + 1 * sgnx, y + i * sgny});
    }
    solve2(n - m + 1, m, x + (m - 1) * sgnx, y, sgnx, sgny);
}

inline void solve1 (int n, int m, int x, int y, int sgnx, int sgny) {
    LOG(1, n, m);
    if (n == m) {
        if (n & 1) {
            for (int i = 1; i <= n; i += 2) {
                ans.pb({x + i * sgnx, y + sgny});
            }
            for (int i = 3; i < n; i += 2) {
                ans.pb({x + i *sgnx, y + n * sgny});
            }
        }
        else {
            for (int i = 1; i <= n; i += 2) {
                ans.pb({x + i * sgnx, y + sgny});
            }
            for (int i = 2; i < n; i += 2) {
                ans.pb({x + i * sgnx, y + n * sgny});
            }
        }
        return;
    }
    if (n < m) {
        for (int i = 1; i <= n; i += 2) {
            ans.pb({x + i * sgnx, y + sgny});
        }
        if (n & 1) {
            solve2(n, m - n, x, y + n * sgny, sgnx, sgny);
        }
        else {
            solve1(n, m - n, x, y + n * sgny, sgnx, sgny);
        }
        return;
    }
    for (int i = 1; i <= m; i += 2) {
        ans.pb({x + sgnx, y + i * sgny});
    }
    if (m & 1) {
        solve2(n - m, m, x + m * sgnx, y, sgnx, sgny);
    }
    else {
        solve1(n - m, m, x + m * sgnx, y, sgnx, sgny);
    }
}

int main() {
//    freopen("input.txt", "r", stdin);
//    freopen("output.txt", "w", stdout);

    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

//    int n;
//    cin >> n;
//    for (int i = 1; i < n; i++) {
//        for (int j = i + 1; j < n; j++) {
//            int res = f(i, j);
//            int go = (i + 1) / 2 + f(i, j - i);
//            if (res != go) {
//                LOG(i, j, res, go);
//            }
//        }
//    }
    int n, m;
    cin >> n >> m;
    solve1(n, m, 0, 0, 1, 1);
    solve2(n, m, 0, 0, 1, 1);
    cout << len(ans) << '\n';
    for (auto &i : ans) {
        cout << i.first << ' ' << i.second << '\n';
    }
}