//和谐俱乐部 - 二分优化 #include<bits/stdc++.h> using namespace std; struct node { int a, b; } man[100009]; bool Cmp (node x, node y) { return (x.a!=y.a? x.a<y.a:x.b>y.b); } int f[100005]; int main() { //freopen("Beautiful.in","r",stdin); //freopen("Beautiful.out","w",stdout); int n,longest=1; scanf("%d", &n); for(int i=1; i<=n; ++i) scanf("%d%d", &man[i].a,&man[i].b); sort (man+1, man+1+n, Cmp); f[1]=man[1].b; for(int i=2; i<=n; ++i) { if(f[longest]<man[i].b) f[++longest]=man[i].b; else { int L=0,R=longest; while(L<=R) //二分查找 { int mid=(L+R)>>1; if(f[mid]<man[i].b) { L=mid+1; if(f[mid+1]>man[i].b) break; } else R=mid-1; } f[L]=man[i].b; } } printf("%d\n", longest); return 0; }