#include <bits/stdc++.h>
using namespace std;
int inf;
const double eps = 1e-8;
const double pi = acos(-1.0);
template <class T, class T2>
int chkmin(T &a, T2 b) {
  return a > b ? a = b, 1 : 0;
}
template <class T, class T2>
int chkmax(T &a, T2 b) {
  return a < b ? a = b, 1 : 0;
}
template <class T>
T sqr(T a) {
  return a * a;
}
template <class T, class T2>
T mmin(T a, T2 b) {
  return a < b ? a : b;
}
template <class T, class T2>
T mmax(T a, T2 b) {
  return a > b ? a : b;
}
template <class T>
T aabs(T a) {
  return a < 0 ? -a : a;
}
template <class T>
int dcmp(T a, T b) {
  return a > b;
}
template <int *a>
int cmp_a(int first, int second) {
  return a[first] < a[second];
}
struct __INIT__ {
  __INIT__() { memset(&inf, 0x3f, sizeof(inf)); }
} __INIT___;
namespace io {
const int SIZE = (1 << 21) + 1;
char ibuf[SIZE], *iS, *iT, obuf[SIZE], *oS = obuf, *oT = oS + SIZE - 1, c,
                                       qu[55];
int f, qr;
inline void flush() {
  fwrite(obuf, 1, oS - obuf, stdout);
  oS = obuf;
}
inline void putc(char first) {
  *oS++ = first;
  if (oS == oT) flush();
}
template <typename A>
inline bool read(A &first) {
  for (f = 1, c = (iS == iT ? (iT = (iS = ibuf) + fread(ibuf, 1, SIZE, stdin),
                              (iS == iT ? EOF : *iS++))
                            : *iS++);
       c < '0' || c > '9';
       c = (iS == iT ? (iT = (iS = ibuf) + fread(ibuf, 1, SIZE, stdin),
                       (iS == iT ? EOF : *iS++))
                     : *iS++))
    if (c == '-')
      f = -1;
    else if (c == EOF)
      return 0;
  for (first = 0; c <= '9' && c >= '0';
       c = (iS == iT ? (iT = (iS = ibuf) + fread(ibuf, 1, SIZE, stdin),
                       (iS == iT ? EOF : *iS++))
                     : *iS++))
    first = first * 10 + (c & 15);
  first *= f;
  return 1;
}
inline bool read(char &first) {
  while ((first = (iS == iT ? (iT = (iS = ibuf) + fread(ibuf, 1, SIZE, stdin),
                               (iS == iT ? EOF : *iS++))
                            : *iS++)) == ' ' ||
         first == '\n' || first == '\r')
    ;
  return first != EOF;
}
inline bool read(char *first) {
  while ((*first = (iS == iT ? (iT = (iS = ibuf) + fread(ibuf, 1, SIZE, stdin),
                                (iS == iT ? EOF : *iS++))
                             : *iS++)) == '\n' ||
         *first == ' ' || *first == '\r')
    ;
  if (*first == EOF) return 0;
  while (!(*first == '\n' || *first == ' ' || *first == '\r' || *first == EOF))
    *(++first) = (iS == iT ? (iT = (iS = ibuf) + fread(ibuf, 1, SIZE, stdin),
                              (iS == iT ? EOF : *iS++))
                           : *iS++);
  *first = 0;
  return 1;
}
template <typename A, typename... B>
inline bool read(A &first, B &...second) {
  return read(first) && read(second...);
}
template <typename A>
inline bool write(A first) {
  if (!first) putc('0');
  if (first < 0) putc('-'), first = -first;
  while (first) qu[++qr] = first % 10 + '0', first /= 10;
  while (qr) putc(qu[qr--]);
  return 0;
}
inline bool write(char first) {
  putc(first);
  return 0;
}
inline bool write(const char *first) {
  while (*first) {
    putc(*first);
    ++first;
  }
  return 0;
}
inline bool write(char *first) {
  while (*first) {
    putc(*first);
    ++first;
  }
  return 0;
}
template <typename A, typename... B>
inline bool write(A first, B... second) {
  return write(first) || write(second...);
}
struct Flusher_ {
  ~Flusher_() { flush(); }
} io_flusher_;
}  // namespace io
using io ::putc;
using io ::read;
using io ::write;
int a[200005];
int s[200005], cnt[200005], las[200005], ok[200005], preok[200005], t;
int n, l;
bool push(int first) {
  if (!t) {
    s[++t] = first;
    cnt[t] = 1;
    las[t] = first;
    ok[t] = preok[t] = 1;
    return 1;
  }
  while (t > 1 && s[t] < first) {
    if (!ok[t]) return 0;
    las[t - 1] = las[t];
    --t;
  }
  if (s[t] < first) return 0;
  if (s[t] > first) {
    s[++t] = first;
    cnt[t] = 1;
    las[t] = first;
    ok[t] = las[t - 1] <= first;
  } else {
    ++cnt[t];
    las[t] = first;
    while (cnt[t] == l) {
      int w = s[t] + 1;
      --t;
      if (!t || s[t] != w) {
        s[++t] = w;
        cnt[t] = 1;
        las[t] = first;
      } else {
        ++cnt[t];
        las[t] = first;
      }
    }
    ok[t] = (t == 1 && cnt[t] == 1) || (t > 1 && las[t - 1] <= s[t]);
  }
  preok[t] = ok[t] && preok[t - 1];
  return 1;
}
signed main() {
  read(n, l);
  for (int i = 1; i <= n; ++i) read(a[i]);
  int ans = 0;
  preok[0] = 1;
  for (int i = n; i; --i) {
    t = 0;
    for (int j = i; j <= n; ++j) {
      if (!push(a[j])) break;
      ans += preok[t];
    }
  }
  write(ans, '\n');
  return 0;
}
