#include <bits/stdc++.h>
using namespace std;
int xx[4] = {1, -1, 0, 0};
int yy[4] = {0, 0, 1, -1};
const double eps = 1e-9;
const int maxn = 2e6 + 5000;
const long long mod = 1e9 + 7;
const int INF(0x3f3f3f3f);
const long long INFL(0x3f3f3f3f3f3f3f3fll);
inline int sign(double a) { return a < -eps ? -1 : a > eps; }
long long mul(long long a, long long b, long long c) {
  long long res = 1;
  while (b) {
    if (b & 1) res *= a, res %= c;
    a *= a, a %= c, b >>= 1;
  }
  return res;
}
long long phi(long long x) {
  long long res = x;
  for (long long i = 2; i * i <= x; i++) {
    if (x % i == 0) res = res / i * (i - 1);
    while (x % i == 0) x /= i;
  }
  if (x > 1) res = res / x * (x - 1);
  return res;
}
template <typename A, typename B>
inline bool chmin(A& a, B b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
template <typename A, typename B>
inline bool chmax(A& a, B b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <typename A, typename B>
inline long long add(A x, B y) {
  if (x + y < 0) return x + y + mod;
  return x + y >= mod ? x + y - mod : x + y;
}
template <typename A, typename B>
inline void add2(A& x, B y) {
  if (x + y < 0)
    x = x + y + mod;
  else
    x = (x + y >= mod ? x + y - mod : x + y);
}
template <typename A, typename B>
inline long long mul1(A x, B y) {
  return 1ll * x * y % mod;
}
template <typename A, typename B>
inline void mul2(A& x, B y) {
  x = (1ll * x * y % mod + mod) % mod;
}
template <typename A>
inline void debug(A a) {
  cout << a << '\n';
}
template <typename A>
inline long long sqr(A x) {
  return 1ll * x * x;
}
template <typename A>
A inv(A x) {
  return mul(x, mod - 2);
}
template <typename A>
void bugl(A a[], int l, int r) {
  for (int i = l; i <= r; i++) cout << a[i] << " ";
  cout << endl;
}
template <typename A>
void bug(A a[], int l, int r) {
  for (int i = l; i <= r; i++) cout << a[i] << " ";
  cout << endl;
}
template <class T>
void wt(const T& x) {
  cout << x << endl;
}
template <class T>
void wt(const T& x, char c) {
  cout << x << c;
}
template <class T>
void wt(const T& x, const string& s) {
  cout << x << s;
}
template <class T>
void wt(const T& x, int rnd) {
  cout << fixed << setprecision(rnd) << x << endl;
}
inline void debug() { cout << "###!!!" << endl; }
inline long long read() {
  char c = getchar();
  long long x = 0, f = 1;
  while (c < '0' || c > '9') {
    if (c == '-') f = -1;
    c = getchar();
  }
  while (c >= '0' && c <= '9') x = 1ll * x * 10 + c - '0', c = getchar();
  return x * f;
}
int fa[maxn];
int Find(int x) {
  if (x != fa[x]) return fa[x] = Find(fa[x]);
  return fa[x];
}
long long n, x;
int a[maxn];
int vis2[maxn];
int vis1[maxn];
int main() {
  while (cin >> n >> x) {
    vector<long long> v;
    for (int i = 1; i <= n; i++) cin >> a[i];
    if (is_sorted(a + 1, a + 1 + n)) {
      cout << x * (x + 1) / 2 << endl;
      continue;
    }
    memset((vis1), -1, sizeof((vis1)));
    memset((vis2), -1, sizeof((vis2)));
    vis2[0] = vis1[0] = 0;
    vis2[x + 1] = vis1[x + 1] = n + 1;
    for (int i = 1; i <= n; i++) {
      if (vis1[a[i]] == -1) vis1[a[i]] = i;
      vis2[a[i]] = i;
    }
    long long Min = 0;
    for (int i = 0; i <= x - 1; i++) {
      if (vis1[i] == -1) {
        v.push_back(Min);
        continue;
        ;
      } else if (vis1[i] < Min) {
        break;
      }
      Min = vis2[i];
      v.push_back(Min);
    }
    for (auto d : v) {
    }
    long long ans = 0;
    Min = n + 1;
    for (int i = x + 1; i >= 2; i--) {
      if (vis2[i] > Min) {
        break;
      }
      if (vis1[i] != -1) {
        Min = vis1[i];
      }
      long long id = upper_bound((v).begin(), (v).end(), Min) - v.begin();
      ans += id;
    }
    cout << ans << endl;
  }
  return 0;
}
