#include<bits/stdc++.h>
#define int ll
using namespace std;
#define endl '\n'
typedef long long ll;

signed main()
{
	ios::sync_with_stdio(0);
	cout.tie(0);
	cin.tie(0);
	//freopen("out.txt", "w", stdout);
	int n, m; cin >> n >> m;
	bool flag = false;
	if (m > n)
		flag = true;

	if (flag) //m>n
	{
		swap(m, n);

		int x = 0;
		if ((n - 1) % m == 0)x = 0;
		else
		{
			x = ((n - 1) / m + 1) * m + 1;
			x = m - (x - n) * 2;
			x = max(0, x);
		}
		cout << ((n - 1) / m + 1)*m + x << endl;


		for (int i = 1; i <= n; i += m)
			for (int k = 1; k <= m; k++)
				cout << k << " " << i << endl;
		if (x)
			for (int i = (m - x) / 2 + 1; i <= (m - x) / 2 + x; i++)
				cout << i << " " << n << endl;
	}
	else//n>=m
	{
		int x = 0;
		if ((n - 1) % m == 0)x = 0;
		else
		{
			x = ((n - 1) / m + 1) * m + 1;
			x = m - (x - n) * 2;
			x = max(0, x);
		}
		cout << ((n - 1) / m + 1)*m + x << endl;

		for (int i = 1; i <= n; i += m)
			for (int k = 1; k <= m; k++)
				cout << i << " " << k << endl; //((n-1)/m+1)*m
		if (x)
			for (int i = (m - x) / 2 + 1; i <= (m - x) / 2 + x; i++)
				cout << n << " " << i << endl;
	}
	return 0;
}

answer.code: In function ‘int main()’:
answer.code:28:32: error: no matching function for call to ‘max(int, ll&)’
   28 |                         x = max(0, x);
      |                             ~~~^~~~~~
In file included from /usr/include/c++/11/bits/specfun.h:45,
                 from /usr/include/c++/11/cmath:1927,
                 from /usr/include/x86_64-linux-gnu/c++/11/bits/stdc++.h:41,
                 from answer.code:1:
/usr/include/c++/11/bits/stl_algobase.h:254:5: note: candidate: ‘template<class _Tp> constexpr const _Tp& std::max(const _Tp&, const _Tp&)’
  254 |     max(const _Tp& __a, const _Tp& __b)
      |     ^~~
/usr/include/c++/11/bits/stl_algobase.h:254:5: note:   template argument deduction/substitution failed:
answer.code:28:32: note:   deduced conflicting types for parameter ‘const _Tp’ (‘int’ and ‘ll’ {aka ‘long long int’})
   28 |                         x = max(0, x);
      |                             ~~~^~~~~~
In file included from /usr/include/c++/11/bits/specfun.h:45,
                 from /usr/include/c++/11/cmath:1927,
                 from /usr/include/x86_64-linux-gnu/c++/11/bits/stdc++.h:41,
                 from answer.code:1:
/usr/include/c++/11/bits/stl_algobase.h:300:5: note: candidate: ‘template<class _Tp, class _Compare> constexpr const _Tp& std::max(const _Tp&, const _Tp&, _Compare)’
  300 |     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/11/bits/stl_algobase.h:300:5: note:   template argument deduction/substitution failed:
answer.code:28:32: note:   deduced conflicting types for parameter ‘const _Tp’ (‘int’ and ‘ll’ {aka ‘long long int’})
   28 |                         x = max(0, x);
      |                             ~~~^~~~~~
In file included from /usr/include/c++/11/string:52,
                 from /usr/include/c++/11/bits/locale_classes.h:40,
                 from /usr/include/c++/11/bits/ios_base.h:41,
                 from /usr/include/c++/11/ios:42,
                 from /usr/include/c++/11/istream:38,
                 from /usr/include/c++/11/sstream:38,
                 from /usr/include/c++/11/complex:45,
                 from /usr/include/c++/11/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/11/bits/stdc++.h:54,
                 from answer.code:1:
/usr/include/c++/11/bits/stl_algo.h:3461:5: note: candidate: ‘template<class _Tp> constexpr _Tp std::max(std::initializer_list<_Tp>)’
 3461 |     max(initializer_list<_Tp> __l)
      |     ^~~
/usr/include/c++/11/bits/stl_algo.h:3461:5: note:   template argument deduction/substitution failed:
answer.code:28:32: note:   mismatched types ‘std::initializer_list<_Tp>’ and ‘int’
   28 |                         x = max(0, x);
      |                             ~~~^~~~~~
In file included from /usr/include/c++/11/string:52,
                 from /usr/include/c++/11/bits/locale_classes.h:40,
                 from /usr/include/c++/11/bits/ios_base.h:41,
                 from /usr/include/c++/11/ios:42,
                 from /usr/include/c++/11/istream:38,
                 from /usr/include/c++/11/sstream:38,
                 from /usr/include/c++/11/complex:45,
                 from /usr/include/c++/11/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/11/bits/stdc++.h:54,
                 from answer.code:1:
/usr/include/c++/11/bits/stl_algo.h:3467:5: note: candidate: ‘template<class _Tp, class _Compare> constexpr _Tp std::max(std::initializer_list<_Tp>, _Compare)’
 3467 |     max(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
/usr/include/c++/11/bits/stl_algo.h:3467:5: note:   template argument deduction/substitution failed:
answer.code:28:32: note:   mismatched types ‘std::initializer_list<_Tp>’ and ‘int’
   28 |                         x = max(0, x);
      |                             ~~~^~~~~~
answer.code:48:32: error: no matching function for call to ‘max(int, ll&)’
   48 |                         x = max(0, x);
      |                             ~~~^~~~~~
In file included from /usr/include/c++/11/bits/specfun.h:45,
                 from /usr/include/c++/11/cmath:1927,
                 from /usr/include/x86_64-linux-gnu/c++/11/bits/stdc++.h:41,
                 from answer.code:1:
/usr/include/c++/11/bits/stl_algobase.h:254:5: note: candidate: ‘template<class _Tp> constexpr const _Tp& std::max(const _Tp&, const _Tp&)’
  254 |     max(const _Tp& __a, const _Tp& __b)
      |     ^~~
/usr/include/c++/11/bits/stl_algobase.h:254:5: note:   template argument deduction/substitution failed:
answer.code:48:32: note:   deduced conflicting types for parameter ‘const _Tp’ (‘int’ and ‘ll’ {aka ‘long long int’})
   48 |                         x = max(0, x);
      |                             ~~~^~~~~~
In file included from /usr/include/c++/11/bits/specfun.h:45,
                 from /usr/include/c++/11/cmath:1927,
                 from /usr/include/x86_64-linux-gnu/c++/11/bits/stdc++.h:41,
                 from answer.code:1...