#include<bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(int i=(int)a;i<(int)b;i++)
using ll =long long;

void solve(){
    int N,W;
    cin>>N>>W;
    int L=13;
    vector<int> p(L),sum(1<<L);
    rep(i,0,N){
        int a;
        cin>>a;
        a--;
        p[a]++;
    }
    rep(i,0,1<<L) rep(j,0,L) if(i&(1<<j)) sum[i]+=p[j];
    vector<int> dp(1<<L,N+2);
    dp[0]=0;
    rep(i,0,1<<L){
        int D=(1<<L)-1-i;
        for(int j=D;j>0;j--,j&=D){
            if(sum[j]==0) dp[j+i]=min(dp[j+i],dp[i]);
            if(sum[j]<=W) dp[j+i]=min(dp[j+i],dp[i]+1);
        }
    }
    cout<<dp[(1<<L)-1]<<"\n";
}

int main(){
    solve();
}