#include <iostream>
#include <algorithm>
using namespace std;
const int maxn = 1e5+10;

int n, l, d;
int a[maxn], b[maxn];
pair < int, int > sorted[maxn];

bool check(int x) {

    int curr = 1;

    for (int i = 1 ; i <= n ; i++) {
        if (sorted[i].second <= x) {

            b[curr] = sorted[i].first;
            curr++;

        }
    }

    b[0] = 0;
    b[x+1] = l;

    for (int i = 1 ; i <= x+1 ; i++) {
        if (b[i] - b[i-1] > d) return false;
    }

    return true;

}

void solve() {

    for (int i = 1 ; i <= n ; i++) sorted[i] = {a[i], i};

    sort(sorted+1, sorted+1+n);

    int l = 1, r = n+1, mid;

    while (l < r - 1) {

        mid = (l+r)/2;
        if (!check(mid)) l = mid;
        else r = mid;

    }

    if (r == n+1) cout << -1 << '\n';
    else cout << r << '\n';

}

void fast_io() {

    ios_base :: sync_with_stdio(0);
    cin.tie(nullptr);
    cout.tie(nullptr);
    cerr.tie(nullptr);

}

void read() {

    cin >> n >> l >> d;
    for (int i = 1 ; i <= n ; ++i) cin >> a[i];

}

int main () {

    fast_io();
    read();
    solve();

}