import std.stdio;
import std.algorithm;
import std.string;
import std.range;
import std.array;
import std.conv;
import std.complex;
import std.math;
import std.ascii;
import std.bigint;
import std.container;
import std.typecons;

auto readInts() {
	return array(map!(to!int)(readln().strip().split()));
}
auto readInt() {
	return readInts()[0];
}
auto readLongs() {
	return array(map!(to!long)(readln().strip().split()));
}
auto readLong() {
	return readLongs()[0];
}

const real eps = 1e-10;

void main(){
    auto n = readLong();
    long[] a;
    foreach(i; iota(n)) {
        a ~= readLong();
    }
    auto b = a.dup.sort;
    foreach(ref ai; a) {
        ai = b.assumeSorted.lowerBound(ai).length();
    }
    long ans;
    foreach(i, ai; a) {
        ans += abs(ai-i) % 2;
    }
    writeln(ans/2);
}

