#include<bits/stdc++.h>
using namespace std;
using lint = int64_t;
const int mod = 998244353;

template<typename T> struct FT {
	vector<T> s;
	FT(int n) : s(n) {}
	FT(const vector<T>& A) : s(A) {
		const int N = int(s.size());
		for (int a = 0; a < N; ++a)
			if ((a | (a + 1)) < N) s[a | (a + 1)] += s[a];
	}
	void update(int pos, T dif) { // a[pos] += dif
		for (; pos < (int)s.size(); pos |= pos + 1) s[pos] += dif;
	}
	T query(int pos) { // sum of values in [0, pos)
		T res = 0;
		for (; pos > 0; pos &= pos - 1) res += s[pos-1];
		return res;
	}
	// min pos st sum of [0, pos] >= sum. Returns n if no sum
	int lower_bound(T sum) { //is >= sum, or -1 if empty sum is.
		if (sum <= 0) return -1;
		int pos = 0;
		for (int pw = 1 << 25; pw; pw >>= 1)
			if (pos + pw <= (int)s.size() && s[pos + pw-1] < sum)
				pos += pw, sum -= s[pos-1];
		return pos;
	}
};

int main(){
    cin.tie(nullptr)->sync_with_stdio(false);
    int n;
    cin>>n;
    vector<int>a(n);
    for(int i=0;i<n;i++) cin>>a[i], a[i]--;
    FT<int>seg(vector<int>(n, 1));
    lint ans = 0;
    int mn = n;
    for(int i=0;i<n;i++){
        seg.update(a[i], -1);
        mn = min(mn, a[i]);
        ans += seg.query(n) - seg.query(mn);
    }
    ans += 2 * n;
    cout<<ans/2;
    if(ans&1) cout<<".5\n";
    else cout<<".0\n";
    return 0;
}