#include<cstdio>
#include<iostream>
#include<iomanip>
#include<algorithm>
#include<cmath>
#include<cstring>
#include<string>
#include<vector>
#include<stack>
#include<queue>
#include<set>
#include<map>
#include<list>
#include
 
<deque>
#include<bitset>
#include<cstdlib>
#define LL long long
#define PI acos(-1)
#define eps 1e-8
#define lowbit(x) (x&-x)
#define MOD 1000000007
#define INF 0x3f3f3f3f
#define MEM(a,x) memset(a,x,sizeof(a))
using namespace std;

void read(int &ans)
{
    ans = 0;
    int flag = 0
 
,ch;
    if((ch = getchar()) == ‘-‘) flag = 1;
    else if(ch >= ‘0‘ && ch <= ‘9‘) ans = ch-‘0‘;
    while((ch = getchar()) >= ‘0‘ && ch <= ‘9‘ )    ans = ans*10+ch-‘0‘;
    if(flag)   ans *= -1;
}

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