#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<algorithm>
#define N
#define int long long
#define fo(i,l,r) for(int i=l;i<=r;i++)
#define rf(i,r,l) for(int i=r;i>=l;i--)
using namespace std;
int n;
int max(int x,int y){return x>y?x:y;}
int min(int x,int y){return x<y?x:y;}
void swap(int &x,int &y){int t=x;x=y;y=t;}
int read(){
int sum=0;bool f=0;char c=getchar();
for(;c<48&&c>57;c=getchar())if(c==45)f=1;
for(;c>=48&&c<=57;c=getchar())sum=sum*10+(c&15);
return f?-sum:sum;
}
signed main(){
//freopen(".in","r",stdin);freopen(".out","w",stdout);
return 0;
}