#include <bits/stdc++.h>
#include <bits/extc++.h>
#include <tr2/dynamic_bitset>

#define int int64_t

using namespace std;
using namespace __gnu_pbds;
using namespace __gnu_cxx;

typedef std::tr2::dynamic_bitset<> bitvector;

template<typename T>
using or_set = tree<T, null_type, less<>, rb_tree_tag, tree_order_statistics_node_update>;

template<typename T>
using or_multiset = tree<T, null_type, less_equal<>, rb_tree_tag, tree_order_statistics_node_update>;

int g_sort(vector<int> &a){
    int cnt = 0;
    while(true){
        pair<int, int> fnd = {-1, -1};
        for(int i = 0; i < a.size() - 1; i++)
            for(int j = i + 1; j < a.size(); j++)
                if(a[i] > a[j] && (fnd.second == -1 || a[i] - a[j] > a[fnd.first] - a[fnd.second]))
                    fnd.first = i, fnd.second = j;
        if(fnd.first == fnd.second)
            break;
        swap(a[fnd.first], a[fnd.second]);
        cnt++;
    }
    return cnt;
}

void solve(){
    vector<int> a = {12,7,18,2,9,11,4,5,19,8,0,15,13,1,10,3,14,6,17,16};
    cout << g_sort(a);
}

int32_t main() {
    int test_case = 1;
    //cin >> test_case;
    while(test_case--)
        solve();
}