#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef double db;
#define int long long
const int N = 5000 + 5;
const double eps = 1e-10;
const int mod = 1e9 + 7;
#define endl '\n';
void solve() {
    int n,m;
    cin>>n>>m;
    vector<int>num(15);
    int lx=0;
    for(int i=1,x;i<=n;i++){
        cin>>x;
        num[x]++;
        if(num[x]==1){
            lx+=(1<<(x-1));
        }
    }
    int w=pow(2,13);
    vector<int>dp(w+5,1e9);
    dp[0]=0;
    for (int j = 0; j <= w; j++) {
        vector<int>a1;
        int x1=j;
        while(x1){
            if(x1%2==1){
                a1.push_back(1);
            }else{
                a1.push_back(0);
            }
            x1/=2;
        }
        int l=a1.size();
        for (int z = j; ; z = j & (z - 1)) {
            vector<int>a2;
            int x2=z;
            while(x2){
                if(x2%2==1){
                    a2.push_back(1);
                }else{
                    a2.push_back(0);
                }
                x2/=2;
            }
            int w1=0;
            int f=0;
            for(int i=0;i<l;i++){
                if(i>=a2.size()&&a1[i]==1){
                    w1+=num[i+1];
                    if(w1>m){
                        f=1;
                        break;
                    }
                    continue;
                }else if(i>=a2.size()){
                    continue;
                }
                if(a2[i]==0&&a1[i]==1){
                    w1+=num[i+1];
                }
                if(w1>m){
                    f=1;
                    break;
                }
            }
            if(!f)dp[j] = min(dp[j], dp[z] +1);
            if(z==0)break;
        }
    }
  //  cout<<lx<<endl;
    cout<<dp[lx]<<endl;
}
signed main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
//    cout<<fixed<<setprecision(10);
    int T = 1;
   // cin >> T;
    while (T--) solve();
    return 0;
}