#include<bits/stdc++.h>
using namespace std;

#define mkp make_pair
#define pii pair<int,int>
#define vc vector
#define pb emplace_back

const int N = 5e5+5;

//in&out
inline int read() {
	int x = 0, w = 0; char ch = getchar(); while(!isdigit(ch)) w |= (ch=='-'), ch = getchar();
	while(isdigit(ch)) x = (x*10)+(ch^48), ch=getchar(); return w?-x:x;
}
inline void write(int x) { if(x<0) putchar('-'), x = -x; if(x>9) write(x/10); putchar(x%10+'0'); }
inline void writec(int x) { write(x); putchar(32); }
inline void writee(int x) { write(x); putchar(10); }

int n, m, idx;
pii a[N];
vc<pii> ans;
set<pii> S;
map<int, int> A, B;
bool vis[N];

int deg[N];
vc<int> G[N];
inline void add(int x, int y) {
	++deg[x]; ++deg[y];
	G[x].pb(y); G[y].pb(x);
}

inline void dfs(int x, int fl, int fa, int rt) {
	int ed = 0; vis[x] = 1;
	for(auto y:G[x]) if(y != fa) {
		if(!vis[y]) dfs(y, fl ^ 1, x, rt);
		else if(y == rt) ed = 1;
	}
	if(fl && !ed) ans.pb(a[x]);
}

signed main() {
	n = read(), m = read();
	for(int i = 1; i <= n; i++) {
		if(i == 1 || i == n) {
			for(int j = 1; j <= m; j++) S.insert(mkp(i,j));
		}
		else S.insert(mkp(i, 1)), S.insert(mkp(i, m));
	}
	for(auto u: S) {
		a[++idx] = u;
		auto [x, y] = u;
		if(A[x + y]) add(A[x + y], idx);
		if(B[x - y]) add(B[x - y], idx);
		A[x + y] = B[x - y] = idx;
	}
	
	for(int i = 1; i <= idx; i++) if(!vis[i] && deg[i] == 1)  dfs(i, 1, 0, i);
	for(int i = 1; i <= idx; i++) if(!vis[i]) dfs(i, 1, 0, i);
	writee(ans.size());
	for(auto u:ans) writec(u.first), writee(u.second);
	return 0;
}