#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef long double ld;
typedef pair<ll, ll> ii;
typedef vector<ll> vi;
typedef vector<vi> vvi;
typedef vector<ii> vii;

#define x first
#define y second
#define pb push_back
#define eb emplace_back
#define all(v) (v).begin(), (v).end()

const ld PI = acos((ld) -1);

bool isSorted(const vi& A) {
	for (ll i = 0; i < A.size()-1; i++) {
		if (A[i+1] < A[i]) return false;
	}
	return true;
}

void run() {
	ll n, k;
	cin >> n >> k;
	vi A(n);
	for (ll i = 0; i < n; i++) {
		cin >> A[i];
	}
	ll res = 0;
	while (!isSorted(A)) {
		res++;
		priority_queue<ll> Q;
		ll j = 0;
		vi An;
		for (ll i = 0; i < n; i++) {
			while (Q.size() < k && j < n) {
				Q.push(-A[j]);
				j++;
			}
			An.pb(-Q.top());
			Q.pop();
		}
		A = An;
	}
	cout << res << endl;
}

signed main() {
    ios_base::sync_with_stdio(false); cin.tie(0);
    run();
    return 0;
}