#include <iostream>
#include <algorithm>
#include <cstdio>
using namespace std;
int main() {
int w, n;
scanf("%d %d", &w, &n);
int *a = new int[n];
for(int i = 0; i < n; i++)
scanf("%d", &a[i]);
sort(a, a+n);
int i = 0, j = n-1, cnt = 0;
while(i <= j) {
if(a[i] + a[j] <= w) {
i++;
}
cnt++;
j--;
}
cout << cnt;
return 0;
}