codeforces 1015A

A. Points in Segments

time limit per test

1 second

memory limit per test

256 megabytes

input

standard input

output

standard output

You are given a set of $\mathrm{nn segments\; on\; the\; axis OxOx,\; each\; segment\; has\; integer\; endpoints\; between 11 and mm inclusive.\; Segments\; may\; intersect,\; overlap\; or\; even\; coincide\; with\; each\; other.\; Each\; segment\; is\; characterized\; by\; two\; integers lili and riri (1\le li\le ri\le m1\le li\le ri\le m)\; —\; coordinates\; of\; the\; left\; and\; of\; the\; right\; endpoints.}$

Consider all integer points between $\mathrm{11 and mm inclusive.\; Your\; task\; is\; to\; print\; all\; such\; points\; that\; don\text{'}t\; belong\; to\; any\; segment.\; The\; point xxbelongs\; to\; the\; segment [l;r][l;r] if\; and\; only\; if l\le x\le rl\le x\le r.}$

Input

The first line of the input contains two integers $\mathrm{nn and mm (1\le n,m\le 1001\le n,m\le 100)\; —\; the\; number\; of\; segments\; and\; the\; upper\; bound\; for\; coordinates.}$

The next $\mathrm{nn lines\; contain\; two\; integers\; each lili and riri (1\le li\le ri\le m1\le li\le ri\le m)\; —\; the\; endpoints\; of\; the ii-th\; segment.\; Segments\; may\; intersect,\; overlap\; or\; even\; coincide\; with\; each\; other.\; Note,\; it\; is\; possible\; that li=rili=ri,\; i.e.\; a\; segment\; can\; degenerate\; to\; a\; point.}$

Output

In the first line print one integer $\mathrm{kk —\; the\; number\; of\; points\; that\; don\text{'}t\; belong\; to\; any\; segment.}$

In the second line print exactly $\mathrm{kk integers\; in any order\; —\; the\; points\; that\; don\text{'}t\; belong\; to\; any\; segment.\; All\; points\; you\; print\; should\; be\; distinct.}$

If there are no such points at all, print a single integer $\mathrm{00 in\; the\; first\; line\; and\; either\; leave\; the\; second\; line\; empty\; or\; do\; not\; print\; it\; at\; all.}$

Examples

input

Copy

3 5
2 2
1 2
5 5

output

Copy

2
3 4 

input

Copy

1 7
1 7

output

Copy

0

Note

In the first example the point $\mathrm{11 belongs\; to\; the\; second\; segment,\; the\; point 22 belongs\; to\; the\; first\; and\; the\; second\; segments\; and\; the\; point 55belongs\; to\; the\; third\; segment.\; The\; points 33 and 44 do\; not\; belong\; to\; any\; segment.}$

In the second example all the points from $\mathrm{11 to 77 belong\; to\; the\; first\; segment.}$

 题意：给你一段1~n的区间，和m次覆盖，从l~r，求没有被覆盖的数

题解：emmm扫一遍覆盖就行，输出没有标记的数

代码如下：

#include <map>
#include <set>
#include <cmath>
#include <ctime>
#include <stack>
#include <queue>
#include <cstdio>
#include <cctype>
#include <bitset>
#include <string>
#include <vector>
#include <cstring>
#include <iostream>
#include <algorithm>
#include <functional>
#define fuck(x) cout<<"["<<x<<"]";
#define FIN freopen("input.txt","r",stdin);
#define FOUT freopen("output.txt","w+",stdout);
//#pragma comment(linker, "/STACK:102400000,102400000")
using namespace std;
typedef long long LL;
typedef pair<int, int> PII;
const int maxn = 100+5;
bool a[maxn];
int ans[maxn];
int main(){
#ifndef ONLINE_JUDGE
    FIN
#endif
    int l,r;
    int n,m;
    while(scanf("%d%d",&n,&m) !=EOF){
        int k=0;
        memset(a,0,sizeof(a));
        while(n--){
            cin>>l>>r;
            for(int i=l;i<=r;i++){
                a[i]=i;
            }
        }
        for(int i=1;i<=m;i++){
            if(a[i]==0){
                ans[k++]=i;
            }
        }
        if(k==0){
            puts("0");
        }else{
            cout<<k<<endl;
            for(int i=0;i<k;i++){
                cout<<ans[i]<<" ";
            }
            puts("");
        }
    }
    return 0;
}