#include<bits/stdc++.h>
using namespace std;

#define ll long long
#define ull unsigned long long
#define ld  long double

using LL = long long; using ULL = unsigned long long;
using VI = vector<int>; using VVI = vector<VI>; using VVVI = vector<VVI>;
using VL = vector<LL>; using VVL = vector<VL>; using VVVL = vector<VVL>;
using VB = vector<bool>; using VVB = vector<VB>; using VVVB = vector<VVB>;
using VD = vector<double>; using VVD = vector<VD>; using VVVD = vector<VVD>;
using VC = vector<char>; using VS = vector<string>; using VVC = vector<VC>;
using PII = pair<int,int>; using PLL = pair<LL,LL>; using PDD = pair<double,double>; using PIL = pair<int,LL>;
using MII = map<int,int>; using MLL = map<LL,LL>;
using SI = set<int>; using SL = set<LL>;
using MSI = multiset<int>; using MSL = multiset<LL>;
template<class T> using MAXPQ = priority_queue<T>;
template<class T> using MINPQ = priority_queue< T, vector<T>, greater<T> >;

const ll MOD = 1000000007;
const ll MOD2 = 998244353;
const ll INF = 1LL << 60;
#define PI  3.14159265358979323846

#define FOR(i, a, b) for(int i = (a); i < (b); ++i)
#define REP(i, n) FOR(i, 0, n)
#define EACH(e, v) for(auto &e : v)
#define RITR(it, v) for(auto it = (v).rbegin(); it != (v).rend(); ++it)
#define ALL(v) v.begin(),v.end()

vector<ll> x8={1,1,1,0,0,-1,-1,-1},y8={1,0,-1,1,-1,1,0,-1};
int dx4[4]={1,-1,0,0}, dy4[4]={0,0,1,-1};

/*
memo
-uf,RMQ(segtree),BIT,BIT2,SegTree,SegTreeLazy
-isprime,Eratosthenes,gcdlcm,factorize,divisors,modpow,moddiv
nCr(+modnCr,inverse,extend_euclid.powmod),tobaseB,tobase10
-dijkstra,Floyd,bellmanford,sccd,topological,treediamiter
-compress1,compress2,rotate90

-co,ci,fo1,fo2,fo3,fo4
-bitsearch,binaryserach
-bfs
-SegTreedec,SegTreeLazydec
*/



int main(){
    cin.tie(0);
    ios_base::sync_with_stdio(0);
    ll N,M,T; cin >> N >> M >> T;
    VL a(M); for(ll i = 0; i < M; i++) cin >> a[i], a[i]--;

    sort(ALL(a));

    VL time(N,0);
    set<PLL> l,r;
    ll j = 0;
    l.insert({INF,INF});
    r.insert({INF,INF});
    for(ll i = 0; i < N; i++) r.insert({0,i});

    for(ll i = 0; i < M; i++){
        while(j < N and j < a[i]){
            l.insert({time[j],j});
            r.erase({time[j],j});
            j++;
        }

        auto [lt,lid] = *l.begin();
        auto [rt,rid] = *r.begin();

        ll t,id,lr = 0;
        if(lt <= rt) t = lt, id = lid, lr = 0;
        else t = rt, id = rid, lr = 1;

        if(time[a[i]]+1 <= t+T){
            r.erase({time[a[i]],a[i]});
            time[a[i]]++;
            r.insert({time[a[i]],a[i]});
        }
        else{
            if(lr) r.erase({time[id],id});
            else l.erase({time[id],id}); 
            time[id] += T;
            if(lr) r.insert({time[id],id});
            else l.insert({time[id],id}); 
        }
    }

    ll ans = *max_element(ALL(time));

    //for(ll i = 0; i < N; i++) cout << time[i] << " ";


    cout << ans << '\n';
/*
    VL agn(N,0);
    for(ll i = 0; i < N; i++) agn[a[i]]++;

    ll emp = 0, free = N;
    for(ll i = 0; i < N; i++) if(agn[i]) emp += agn[i]-1, free--; 
*/  
    
    
}