#include <bits/stdc++.h>
using namespace std;
template <typename T, typename T1>
ostream &operator<<(ostream &out, pair<T, T1> obj) {
  out << "(" << obj.first << "," << obj.second << ")";
  return out;
}
template <typename T, typename T1>
ostream &operator<<(ostream &out, map<T, T1> cont) {
  typename map<T, T1>::const_iterator itr = cont.begin();
  typename map<T, T1>::const_iterator ends = cont.end();
  for (; itr != ends; ++itr) out << *itr << " ";
  out << endl;
  return out;
}
template <typename T>
ostream &operator<<(ostream &out, set<T> cont) {
  typename set<T>::const_iterator itr = cont.begin();
  typename set<T>::const_iterator ends = cont.end();
  for (; itr != ends; ++itr) out << *itr << " ";
  out << endl;
  return out;
}
template <typename T>
ostream &operator<<(ostream &out, multiset<T> cont) {
  typename multiset<T>::const_iterator itr = cont.begin();
  typename multiset<T>::const_iterator ends = cont.end();
  for (; itr != ends; ++itr) out << *itr << " ";
  out << endl;
  return out;
}
template <typename T,
          template <typename ELEM, typename ALLOC = allocator<ELEM>> class CONT>
ostream &operator<<(ostream &out, CONT<T> cont) {
  typename CONT<T>::const_iterator itr = cont.begin();
  typename CONT<T>::const_iterator ends = cont.end();
  for (; itr != ends; ++itr) out << *itr << " ";
  out << endl;
  return out;
}
template <typename T, unsigned int N, typename CTy, typename CTr>
typename enable_if<!is_same<T, char>::value, basic_ostream<CTy, CTr> &>::type
operator<<(basic_ostream<CTy, CTr> &out, const T (&arr)[N]) {
  for (auto i = 0; i < N; ++i) out << arr[i] << " ";
  out << endl;
  return out;
}
template <typename T>
T gcd(T a, T b) {
  T min_v = min(a, b);
  T max_v = max(a, b);
  while (min_v) {
    T temp = max_v % min_v;
    max_v = min_v;
    min_v = temp;
  }
  return max_v;
}
template <typename T>
T lcm(T a, T b) {
  return (a * b) / gcd(a, b);
}
template <typename T>
T fast_exp_pow(T base, T exp, T mod) {
  long long res = 1;
  while (exp) {
    if (exp & 1) {
      res *= base;
      res %= mod;
    }
    exp >>= 1;
    base *= base;
    base %= mod;
  }
  return res % mod;
}
int N, L, Tbeg, Tend, Tmid;
long long S;
long long numbers[100010], dp_solve[100010], seg_tree_1[100010];
pair<long long, long long> seg_tree[4 * 100010];
void build(int Tbeg = 0, int Tend = N - 1, int ind = 0) {
  if (Tbeg == Tend) {
    seg_tree[ind] = make_pair(numbers[Tbeg], numbers[Tbeg]);
    return;
  }
  int Tmid = (Tbeg + Tend) >> 1;
  build(Tbeg, Tmid, 2 * ind + 1);
  build(Tmid + 1, Tend, 2 * ind + 2);
  seg_tree[ind].first =
      min(seg_tree[2 * ind + 1].first, seg_tree[2 * ind + 2].first);
  seg_tree[ind].second =
      max(seg_tree[2 * ind + 1].second, seg_tree[2 * ind + 2].second);
}
pair<long long, long long> query(int Qbeg, int Qend, int Tbeg = 0,
                                 int Tend = N - 1, int ind = 0) {
  if (Tbeg >= Qbeg && Tend <= Qend) return seg_tree[ind];
  if (Tbeg > Qend || Tend < Qbeg) return make_pair(INT_MAX, -INT_MAX);
  int Tmid = (Tbeg + Tend) >> 1;
  pair<long long, long long> ret1 = query(Qbeg, Qend, Tbeg, Tmid, 2 * ind + 1);
  pair<long long, long long> ret2 =
      query(Qbeg, Qend, Tmid + 1, Tend, 2 * ind + 2);
  pair<long long, long long> ret =
      make_pair(min(ret1.first, ret2.first), max(ret1.second, ret2.second));
  return ret;
}
void update_1(int pos, long long value, int Tbeg = 0, int Tend = N,
              int ind = 0) {
  if (Tbeg == Tend && Tbeg == pos) {
    seg_tree_1[ind] = value;
    return;
  }
  if (Tbeg > pos || Tend < pos) return;
  int Tmid = (Tbeg + Tend) >> 1;
  update_1(pos, value, Tbeg, Tmid, 2 * ind + 1);
  update_1(pos, value, Tmid + 1, Tend, 2 * ind + 2);
  if (seg_tree_1[2 * ind + 1] == -1)
    seg_tree_1[ind] = seg_tree_1[2 * ind + 2];
  else if (seg_tree_1[2 * ind + 2] == -1)
    seg_tree_1[ind] = seg_tree_1[2 * ind + 1];
  else
    seg_tree_1[ind] = min(seg_tree_1[2 * ind + 1], seg_tree_1[2 * ind + 2]);
}
long long query_1(int Qbeg, int Qend, int Tbeg = 0, int Tend = N, int ind = 0) {
  if (Tbeg >= Qbeg && Tend <= Qend) return seg_tree_1[ind];
  if (Tbeg > Qend || Tend < Qbeg) return -1;
  int Tmid = (Tbeg + Tend) >> 1;
  long long ret1 = query_1(Qbeg, Qend, Tbeg, Tmid, 2 * ind + 1);
  long long ret2 = query_1(Qbeg, Qend, Tmid + 1, Tend, 2 * ind + 2);
  long long ret;
  if (ret1 == -1)
    ret = ret2;
  else if (ret2 == -1)
    ret = ret1;
  else
    ret = min(ret1, ret2);
  return ret;
}
int main() {
  scanf("%d%lld%d", &N, &S, &L);
  for (auto i = 0; i < N; ++i) scanf("%lld", numbers + i);
  build();
  memset(dp_solve, -1, sizeof(dp_solve));
  memset(seg_tree_1, -1, sizeof(seg_tree_1));
  update_1(0, 0);
  for (auto i = 1; i <= N; ++i) {
    Tbeg = 1, Tend = i;
    while (Tbeg < Tend) {
      Tmid = (Tbeg + Tend) >> 1;
      pair<long long, long long> ret = query(Tmid - 1, i - 1);
      if (ret.second - ret.first <= S)
        Tend = Tmid;
      else
        Tbeg = Tmid + 1;
    }
    if (i - Tend + 1 < L)
      dp_solve[i] = -1;
    else {
      if (i == 1) {
        if (L == 1) dp_solve[i] = 1;
      } else {
        long long ret = query_1(Tend - 1, i - L);
        if (ret != -1) dp_solve[i] = ret + 1;
      }
      update_1(i, dp_solve[i]);
    }
  }
  printf("%lld\n", dp_solve[N]);
  return 0;
}
