#include<bits/stdc++.h>
using namespace std;
const int MAX_N = 1000000;
int main() {
int w,n;
cin>>w>>n;
int prices[MAX_N];
for(int i = 0;i < n;i++) {
cin>>prices[i];
}
sort(prices,prices + n);
int count = 0;
int left = 0,right = n - 1;
while(left <= right){
if(prices[left] + prices[right] <= w){
left++;
right--;
}else{
right--;
}
count++;
}
cout<<count;
return 0;
}
