hiho 第155周 任务分配

/*
#include <cstdio>
#include <algorithm>
#include <cmath>
#include <vector>
#include <cstring>

using namespace std;

const int maxn = 100000+5;

struct BPM {
    int n,m;
    vector<int> G[maxn];
    int left[maxn];
    bool T[maxn];

    int right[maxn];
    bool S[maxn];

    void init(int n,int m) {
        this->n = n;
        this->m = m;
        for(int i=0;i<n;i++)
            G[i].clear();
    }

    void AddEdge(int u,int v) {
        G[u].push_back(v);
    }

    bool match(int u) {
        S[u] = true;
        for(int i=0;i<G[u].size();i++) {
            int v = G[u][i];
            if(!T[v]) {
                T[v] = true;
                if(left[v]==-1||match(left[v])) {
                    left[v] = u;
                    right[u] = v;
                    return true;
                }
            }
        }
        return false;
    }

    int solve() {
        memset(left,-1,sizeof(left));
        memset(right,-1,sizeof(right));
        int ans = 0;
        for(int u=0;u<n;u++) {
            memset(S,0,sizeof(S));
            memset(T,0,sizeof(T));
            if(match(u))
                ans++;
        }
        return ans;
    }

}sol;

struct Node {
    int s,e;
}node[maxn];

int main()
{
    int n;
    scanf("%d",&n);
    sol.init(n,n);
    for(int i=0;i<n;i++)
        scanf("%d%d",&node[i].s,&node[i].e);

    for(int i=0;i<n;i++)
        for(int j=i+1;j<n;j++)
            if(node[i].e<=node[j].s)
                sol.AddEdge(i,j);
            else if(node[i].s>=node[j].e)
                sol.AddEdge(j,i);

    printf("%d\n",n-sol.solve());


    return 0;
}
*/

#include <bits/stdc++.h>

using namespace std;

const int maxn = 100000+5;

struct Node {
    int s,e;
    bool operator < (const Node & rhs) const {
        return s < rhs.s;
    }
}node[maxn];

int main()
{
    int n;
    scanf("%d",&n);
    for(int i=0;i<n;i++)
        scanf("%d%d",&node[i].s,&node[i].e);

    sort(node,node+n);

    priority_queue<int,vector<int>,greater<int> > Q;

    Q.push(node[0].e);
    for(int i=1;i<n;i++) {
        if(Q.top()<=node[i].s)
        {
            Q.pop();
            Q.push(node[i].e);
        }
        else Q.push(node[i].e);
    }
    printf("%d\n",Q.size());

    return 0;
}