#include "shoes.h"
#include "bits/stdc++.h"
#include "ext/pb_ds/assoc_container.hpp"
#include "ext/pb_ds/tree_policy.hpp"
#include "ext/pb_ds/hash_policy.hpp"
using namespace std;
using namespace __gnu_pbds;
template <typename T>
using __indexed_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
long long count_swaps(vector<int> a)
{
int n = a.size();
__indexed_set< pair<int, int> > st;
gp_hash_table<int, queue<int> > mp;
for (int i = 0; i < n; ++i)
{
mp[a[i]].push(i);
st.insert({i, a[i]});
}
long long result = 0;
while(!st.empty())
{
int shoe = st.begin() -> second;
int shoePair = mp[-shoe].front();
result = result + 1LL * (st.order_of_key({shoePair, -shoe})) - (shoe < 0LL);
mp[shoe].pop();
mp[-shoe].pop();
st.erase({shoePair, -shoe});
st.erase(st.begin());
}
return result;
}
