#include<bits/stdc++.h>
#include"shoes.h"
#pragma GCC optimize("unroll-loops,no-stack-protector")
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> pll;
const ll MOD=1e9+7;
const ll MOD2=998244353;
const ll N=5e3+7;
const ll K=350;
const ld pi=acos(-1);
const ll INF=(1LL<<60);
#define SQ(i) ((i)*(i))
#define REP(i,n) for(ll i=0;i<n;i++)
#define REP1(i,n) for(ll i=1;i<=n;i++)
#define pb push_back
#define mp make_pair
#define X first
#define Y second
#define setp setprecision
#define lwb lower_bound
#define SZ(_a) (ll)_a.size()
ll count_swaps(vector<int> s){
ll ans=0;
for(int i=0;i<SZ(s);i+=2){
for(int j=i+1;j<SZ(s);j++){
if(s[j]+s[i]==0){
for(int k=j;k>i+1;k--)++ans,swap(s[k],s[k-1]);
break;
}
}
if(s[i]>s[i+1])++ans,swap(s[i],s[i+1]);
}
return ans;
}
