#include <iostream>
#include <iomanip>
#include <cstdio>
#include <queue>
#include <cstring>
#include <vector>
#include <map>
#include <algorithm>
#include <cctype>
#include <cmath>
#include <bitset>
#include <set>
#include <deque>
#include <stack>
#include <atcoder/all>
#include <array>
using namespace std;
#define rep(i,n) for(int i = 0; i < (int)(n); ++i)
#define rrep(i,n) for(int i = 1; i <= (n); ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
#define srep(i,s,t) for (int i = s; i < (t); ++i)
#define dsrep(i,t,s) for(int i = (t)-1; i >= (s); --i)
#define rng(a) a.begin(),a.end()
#define rrng(a) a.rbegin(),a.rend()
#define isin(x,l,r) ((l) <= (x) && (x) < (r))
int dx4[4]={1,0,-1,0};
int dy4[4]={0,-1,0,1};
using ll = long long;
using uint = unsigned;
using ull = unsigned long long;
using P = pair<int,int>;
const ll LINF = 1001002003004005006ll;
const int INF = 1001001001;
// const ll mod = 998244353;
const ll mod = 1e9 + 7;

///////////////////////////////////////////
int n;
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);

  cin >> n;
  vector<int> pos(n);
  rep(i, n) {
    int a;
    cin >> a;
    pos[--a] = i;
  }

  bool update = true;
  int ans = 0;
  while (update) {
    update = false;
    rep(i, n - 1) {
      if(pos[i] > pos[i + 1]) {
        update = true;
        ans++;
        swap(pos[i], pos[i + 1]);
      }
    }
  }

  cout << ans << endl;
}