#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pll = pair<long long, long long>;
constexpr char ln =  '\n';
//constexpr long long MOD = 1000000007;
constexpr long long MOD = 998244353;
constexpr long long INF = 1000000000 + 100;
constexpr long long LINF = 1000000000000000000 + 100;
#define all(x) (x).begin(),(x).end()
#define rep(i,n) for(int i=0;i<(n);i++)
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }


int main(){
    ll n, k; cin >> n >> k;
    vector<ll> C(n);
    rep(i, n){
        ll a; cin >> a; C[a]++;
    }
    vector<ll> box(k); ll last = k;
    rep(i, n){
        last = min(last, C[i]);
        rep(j, last)box[j] = i+1;
    }
    ll res = accumulate(all(box), 0LL);
    cout << res << ln;
}   
#include <map>
#include <set>
#include <list>
#include <cmath>
#include <deque>
#include <stack>
#include <queue>
#include <array>
#include <bitset>
#include <cstdio>
#include <string>
#include <vector>
#include <random>
#include <chrono>
#include <utility>
#include <numeric>
#include <cstdlib>
#include <cstring>
#include <climits>
#include <sstream>
#include <assert.h>
#include <iostream>
#include <iomanip>
#include <algorithm>
#include <functional>
#include <unordered_map>
using namespace std;

void __print(int x) {cerr << x;}
void __print(long x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(unsigned x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(unsigned long x) {cerr << x;}
void __print(unsigned long long x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(bool x) {cerr << (x ? "true" : "false");}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}

template<typename T, typename V> void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i : x) cerr << (f++ ? "," : ""), __print(i); cerr << "}";} void _print() {cerr << "]\n";}
template <typename T, typename... V>void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifdef HOME
#warning CHECK int:ll::INT_MAX:LLONG_MAX
#define maxn 20
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
#define maxn 2000006
#define gcd __gcd
#define debug(x...)
#endif

#define ff first
#define endl '\n'
#define ss second
#define inf 0x3f3f3f3f
#define MOD 1000000007
#define PI 3.14159265358979323846264338327950L
#define f(i,x,n) for(int i=x;i<=n;i++)
#define fr(i,x,n) for(int i=x;i>=n;i--)
struct _ { ios_base::Init i; _() { ios_base::sync_with_stdio(false), cin.tie(NULL), cout.tie(NULL); } } _;

int dx[] = { -1, 0, 1, 0, -1, -1, 1, 1};
int dy[] = {0, 1, 0, -1, -1, 1, 1, -1};


int main() {

	int n, k; cin >> n >> k;

	map<int, int> freq;
	vector<int> a(n, 0); for (int i = 0; i <= n - 1; i++) cin >> a[i], freq[a[i]]++;

	vector<pair<int, int>> v(freq.begin(), freq.end());

	if (v[0].ff != 0) {
		cout << 0;
		return 0;
	}

	v[0].ss = min(k, v[0].ss);
	long long ans = v[0].ss;

	for (int i = 1; i < v.size(); i++) {
		if (v[i].ff != i) break;
		v[i].ss = min(v[i - 1].ss, v[i].ss);
		ans += v[i].ss;
	}

	cout << ans;

	return 0;
}