#include <bits/stdc++.h>
using namespace std;
using ll=long long;
#define rep(i,n) for(ll i=0;i<n;i++)

int main(){
    int n,m;
    ll t;
    cin >> n >> m >> t;

    vector<ll> a(m);
    rep(i,m){
        cin >> a[i];
        a[i]--;
    }

    ll l=0,r=123;
    while(l+1<r){
        ll k=l+(r-l)/2,count=0;
        vector<ll> b(n,k);
        for(int x:a){
            if(0<b[x]) b[x]--;
            else count++;
        }
        rep(i,n) count-=b[i]/t;
        if(0<count) l=k;
        else r=k;
    }
    cout << r << endl;

}