#include <iostream>
#include <algorithm>

using namespace std;

int main() {
    int w, n;
    cin >> w >> n;
    
    int num[30001];
    for (int i = 0; i < n; i++) {
        cin >> num[i];
    }
    
    sort(num, num + n, greater<int>());
    
    int le = 0, ri = n - 1;
    int cnt = 0;
    
    while (le < ri) {
        cnt++;
        if (num[le] + num[ri] <= w) {
            ri--;
        }
        le++;
    }
    
    cout << cnt << endl;
    
    return 0;
}