// ~~ icebear ~~
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> ii;
typedef pair<int, ii> iii;
template<class T>
bool minimize(T &a, const T &b) {
if (a > b) return a = b, true;
return false;
}
template<class T>
bool maximize(T &a, const T &b) {
if (a < b) return a = b, true;
return false;
}
#define FOR(i,a,b) for(int i=(a); i<=(b); ++i)
#define FORR(i,a,b) for(int i=(a); i>=(b); --i)
#define REP(i, n) for(int i=0; i<(n); ++i)
#define RED(i, n) for(int i=(n)-1; i>=0; --i)
#define MASK(i) (1LL << (i))
#define BIT(S, i) (((S) >> (i)) & 1)
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define all(x) x.begin(), x.end()
#define task "icebear"
const int MOD = 1e9 + 7;
const int inf = 1e9 + 27092008;
const ll INF = 1e18 + 27092008;
const int N = 7000 + 5;
int n, D, a[N], f[N][N];
deque<int> dq[N];
void init(void) {
cin >> n >> D;
FOR(i, 1, n) cin >> a[i];
}
void process(void) {
memset(f, -0x3f, sizeof f);
FOR(i, 1, n) {
maximize(f[i][i], 1);
FOR(j, 1, n) {
if (!dq[j].empty())
maximize(f[i][a[i] > a[j] ? i : j], f[dq[j].front()][j] + (a[i] > a[j]));
}
FOR(j, 1, n) {
while(!dq[j].empty() && f[dq[j].back()][j] <= f[i][j]) dq[j].pop_back();
dq[j].pb(i);
}
}
cout << *max_element(f[n] + 1, f[n] + n + 1);
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
if (fopen(task".inp", "r")) {
freopen(task".inp", "r", stdin);
freopen(task".out", "w", stdout);
}
int tc = 1;
// cin >> tc;
while(tc--) {
init();
process();
}
return 0;
}
