#include <iostream>
#include <set>
#include <cstdio>
using namespace std;
set<int>hel;
int main()
{
    int i,t,n,m,num;
    scanf("%d%d%d",&t,&n,&m);
    while(t--)
    {
        scanf("%d",&num);
        hel.insert(num);
    }
    int f=n-m;
    for(i=1;*hel.end()>i*m;i++)
    {
        hel.insert(*hel.end()-f);
        hel.erase(*hel.end());
    }
    printf("%d\n",i);
    return 0;
}
