#include "shoes.h"
#include <bits/stdc++.h>
#define rep(i, n) for(ll i = 0; i < ll(n); i++)
#define rep2(i, s, n) for(ll i = ll(s); i < ll(n); i++)
#define rrep(i, n) for(ll i = ll(n)-1; i >= 0; i--)
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define pb push_back
#define eb emplace_back
using namespace std;
using ll = long long;
using P = pair<int, int>;
using vi = vector<int>;
using vvi = vector<vi>;
using vl = vector<ll>;
using vvl = vector<vl>;
using vp = vector<P>;
using vvp = vector<vp>;
using vb = vector<bool>;
using vvb = vector<vb>;
using vs = vector<string>;
template<class T>
bool chmin(T &a, T b) {
if (a > b) {
a = b;
return true;
}
return false;
}
template<class T>
bool chmax(T &a, T b) {
if (a < b) {
a = b;
return true;
}
return false;
}
const int inf = 1001001001;
const ll linf = 1001001001001001001;
ll count_swaps(vi s) {
int n = s.size() / 2;
return (ll) n * (n - 1) / 2;
// vvi l(n), r(n);
// rep(i, 2 * n) {
// if (s[i] < 0) l[-s[i] - 1].pb(i);
// else r[s[i] - 1].pb(i);
// }
// vp v;
// rep(i, n) rep(j, l[i].size()) v.eb(l[i][j], r[i][j]);
// sort(all(v));
// vi ls;
// for (auto[i, j] : v) ls.pb(i), ls.pb(j);
// ll ans = 0;
// rep(i, 2 * n)
// rep2(j, i + 1, 2 * n){
// ans += ls[i] > ls[j];
// }
// return ans;
}
