#include <map>
#include <ext/pb_ds/assoc_container.hpp>
#include "shoes.h"
using namespace std;
using namespace __gnu_pbds;
template<typename T, typename Tk>
using os_map = tree<
T, Tk, less<T>, rb_tree_tag, tree_order_statistics_node_update
>;
template<typename T>
using os_set = os_map<T, null_type>;
long long count_swaps(vector<int> S)
{
const size_t n = S.size();
vector<vector<size_t>> pos(2*n);
for(size_t i = n; i --> 0; )
pos[S[i] + n].push_back(i);
os_set<size_t> erased;
size_t mex = 0;
long long result = 0;
while(erased.size() < n)
{
while(erased.find(mex) != erased.end())
mex++;
auto i = pos[-S[mex] + n].back();
result += i - (mex + 1) - (erased.order_of_key(i) - erased.order_of_key(mex));
if(S[mex] > 0)
result++;
erased.insert(mex);
pos[S[mex] + n].pop_back();
erased.insert(i);
pos[-S[mex] + n].pop_back();
}
return result;
}
