#include<bits/stdc++.h>
using namespace std;
#define rep(i,x,y) for (int i=(x);i<=(y);i++)
#define drep(i,y,x) for (int i=(y);i>=(x);i--)
#define pii pair<int,int>
#define fir first
#define sec second
#define MP make_pair
#define templ template<typename T>
templ bool chkmin(T &x,T y){return x>y?x=y,1:0;}
templ bool chkmax(T &x,T y){return x<y?x=y,1:0;}
void file() {
    #ifdef zqj
    freopen("a.in","r",stdin);
    #endif
}
#define sz 122222

int n,m;
// array<int,3>a[sz<<1];
vector<pii>V[sz<<1];

int main() {
    file();
    ios::sync_with_stdio(false),cin.tie(0);
    cin>>n>>m;
    rep(i,2,n+m) {
        int l=2-i,r=2*n-i;
        chkmin(r,i-2);
        chkmax(l,i-2*m);
        chkmax(l,1-m);
        chkmin(r,n-1);
        assert(l<=r);
        l+=m,r+=m;
        V[l].push_back({r,i});
    }
    vector<pii>ans;
    priority_queue<pii,vector<pii>,greater<pii>>q[2];
    rep(j,1,n+m-1) {
        for (auto [r,id]:V[j]) q[j&1].push({r,id});
        while (q[j&1].size()&&q[j&1].top().fir<j) q[j&1].pop();
        if (q[j&1].size()) {
            auto [r,id]=q[j&1].top(); q[j&1].pop();
            ans.push_back({(id+(j-m))/2,(id-(j-m))/2});
        }
    }
    cout<<ans.size()<<'\n';
    for (auto [x,y]:ans) cout<<x<<' '<<y<<'\n';
    return 0;
}