#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pii;
typedef vector<ll> vi;
typedef vector<vi> matrix;
#define rep(i, a, b) for(ll i = a; i < b; i++)
#define down(i, b, a) for(ll i = b - 1; i >= a; i--)
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
ll n, m;
cin >> n >> m;
vi p(n);
rep(i, 0, n) cin >> p[i];
rep(i, 0, n){
p[i] = m * (i + 1) - p[i];
}
vi dp(0);
rep(i, 0, n){
if(p[i] < 0) continue;
ll best = dp.size();
ll l = 0, r = dp.size() - 1;
while(l <= r){
ll m = (l + r) / 2;
if(dp[m] > p[i]){
best = m;
r = m - 1;
}
else l = m + 1;
}
if(best == dp.size()) dp.push_back(p[i]);
else{
dp[best] = p[i];
}
}
cout << n - dp.size() << endl;
}
