#include <bits/stdc++.h>
#include "shoes.h"
#define startt ios_base::sync_with_stdio(false);cin.tie(0);
typedef long long ll;
using namespace std;
#define vint vector<int>
#define all(v) v.begin(), v.end()
#define MOD 1000000007
#define MOD2 998244353
#define MX 1000000000
#define MXL 1000000000000000000
#define PI (ld)2*acos(0.0)
#define nax 200005
#define pb push_back
#define sc second
#define fr first
//#define int long long
#define endl '\n'
#define ld long double
#define NO cout << "NO" << endl
#define YES cout << "YES" << endl
long long count_swaps(vector<int> S)
{
return (S.size()/2)*(S.size()/2-1)/2;
}
/*
int main()
{
int n, l, u;
cin >> n >> l >> u;
vint a(n);
for(int i = 0; i < n; i++)
{
cin >> a[i];
}
vint ans = find_subset(l, u, a);
for(auto x : ans)
{
cout << x << " ";
}
cout << endl;
}
*/
