#include <iostream>#include <stdio.h>#include <string.h>#include <algorithm>using namespace std;struct node{ int x,y; bool f;};const int maxn=2*200005;node a[maxn];node ans[maxn];int n,m;bool cmp(node a,node b){ if (a.x==b.x && a.y==b.y) return a.f; if( a.y == b.y ) return a.x < b.x; return a.y > b.y;}bool cmpp(node p,node q){ if (p.x==q.x) return p.y<q.y; else return p.x<q.x;}int main(){ int i; while (scanf("%d%d",&n,&m)!=EOF) { for (i=1;i<=n;i++) { scanf("%d%d",&a[i].x,&a[i].y); a[i].f=false; } for (i=n+1;i<=n+m;i++) { scanf("%d%d",&a[i].x,&a[i].y); a[i].f=true; } sort(a+1,a+n+m+1,cmp); int t=0; int Min=1000000005; for (i=1;i<=n+m;i++) { if (a[i].f) { if (a[i].x<Min) Min=a[i].x; } else { if (a[i].x < Min) { t++; ans[t].x=a[i].x; ans[t].y=a[i].y; } } } sort(ans+1,ans+t+1,cmpp); printf("%dn",t); for (i=1;i<=t;i++) printf("%d %dn",ans[i].x,ans[i].y); } return 0;}
