#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
typedef long long ll;
using namespace std;
using namespace __gnu_pbds;
#define FOR(i, x, y) for(ll i=x; i<y; i++)
#define FORNEG(i, x, y) for(ll i=x; i>y; i--)
#define ordered_set tree<ll, null_type,less_equal<ll>, rb_tree_tag,tree_order_statistics_node_update>
#define fast() ios_base::sync_with_stdio(false);cin.tie(NULL)
ll temp;
ll n,d,m;
ll lis[1000001];
bool check(ll x){
ll cur = 0;
FOR(i,0,n){
cur += lis[i];
cur -= x;
if (cur >= x*d){
return false;
}
}
return true;
}
void sus(ll x){
}
int main(){
cin >> n >> d >> m;
FOR(i,0,n){
cin >> temp;
lis[temp-1] += 1;
}
ll lo = 0;
ll hi = 1000001;
while (lo<hi){
ll mid = (lo+hi)/2;
if (check(mid)){
hi = mid;
}else{
lo = mid+1;
}
}
cout << lo;
}
