本蒟蒻习惯
/* make by ltao */
#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <fstream>
#include <math.h>
#include <stdio.h>
#include <time.h>
#include <string.h>
#include <queue>
#include <deque>
#include <stack>
#include <vector>
#include <list>
#include <map>
#include <algorithm>
#include <string>
#include <complex> //复数类
#include <sstream>
#include <set>
typedef long long ll;
typedef unsigned long long ull;
typedef double db;
#define sz 666666
#define fake int
#define re return
#define diss(u) dis[u]+h[u]
#define get() getchar()
#define inf 1e6
using namespace std;
int read(){
int x=0;bool f=0;
char ch=get();
while(ch<'0'||ch>'9'){
if(ch=='-') f=1;
ch=get();
}
while(ch<='9'&&ch>='0'){
x=(x<<1)+(x<<3)+(ch-'0');
ch=get();
}
return f?-x:x;
}