include <bits/stdc++.h>

using namespace std;

int main() { int n, w, a[30000], j = 1, k, ans = 0; cin >> w >> n;

for (int i = 1; i <= n; i++) {

cin >> a[i]; }

sort(a + 1, a + n + 1);

for (k = n; k >= j; k--) {

if (a[j] + a[k] <= w) { j++; ans++; } else { ans++; } }

cout << ans; return 0; }