#include <cstdio>
#include <algorithm>

using namespace std;

int main()
{
    int n, max, up, down = 0, counter = 0, left;
    scanf("%i%i",&max,&n);
    int tablica[n];
    for(int i=0;i<n;i++)scanf("%i",&tablica[i]);
    sort(tablica, tablica+n);
    up = n-1; left = n;
    while(left>1){
        if(tablica[down]+tablica[up]<=max){
            counter++;
            up--;
            down++;
            left -= 2;
        }
        else{
            counter++;
            up--;
            left--;
        }
    }
    if(left==1)counter++;
    printf("%i",counter);
    return 0;
}