#include<bits/stdc++.h>
using namespace std;
int a[10005],n,i,t,ans,k,l,r,cnt;
priority_queue <int> q;
int main(){
    cin>>t;
    cin>>n;
    for(i=0;i<n;i++){
        cin>>k;
        q.push(k);
    }
    i=n-1;
    while(!q.empty()){
        a[i]=q.top();
        q.pop();
        i--;
    }
    r=n-1;
    cnt=n;
    while(l!=r&&(r-l)!=1){
        if((a[l]+a[r])<=t){
            ans++;
            l++;
            r--;
            cnt-=2;
        } else{
            r--;
            ans++;
            cnt-=1;
        }
    }
    if(cnt) ans++;
    cout<<ans;
    return 0;
}

堆排序+双指针