#include<bits/stdc++.h>
using namespace std;
#define int long long
#define lowbit(x) (x & (-x))
typedef long long ll;
typedef pair<int,int> pii;
mt19937 rnd(time(0));
const int N = 1e5 + 7;
const int mod = 1e9 + 9;
int a[15],f[1 << 15];
bool vis[15],now[15],v[1 << 15];
int n , w , cnt; 
queue<int> q;
void dfs(int x) {
    if(x == 13) {
        int res = 0;
        for(int i = 0;i < 13;i++) 
            if(now[i]) res += a[i];
        int id = 0;
        for(int i = 0;i < 13;i++) 
            if(now[i] || vis[i]) id += (1 << i);
        if(res <= w) {
            f[id] = min(f[id],f[cnt] + 1);
            if(id != cnt) q.push(id);
        }
        return ;
    }
    dfs(x + 1);
    if(!vis[x]) {
        now[x] = 1;
        dfs(x + 1);
        now[x] = 0;
    }
}
void dp(int x) {
    if(v[x]) return ;
    for(int i = 0;i < 13;i++) vis[i] = 0;
    for(int i = 0;i < 13;i++) {
        if(1 << i & x) vis[i] = 1;
    }
    cnt = x;
    dfs(0);
    v[x] = 1;
}
void solve() {
    cin >> n >> w;
    for(int i = 1;i <= n;i++) {
        int t; cin >> t;
        a[t - 1]++;
    }
    f[0] = 0;
    for(int i = 1;i < (1 << 13);i++) f[i] = 1e16;
    q.push(0);
    while(!q.empty()) 
        dp(q.front()),q.pop();
    cout << f[(1 << 13) - 1] << "\n";
}
signed main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    int t = 1;
    // cin >> t;
    while(t--) solve();
    return 0;
}