#include<iostream> #include<algorithm> using namespace std; int main() { int arr[50000] = {},w,n,i,left=0,right,ans=0; cin >> w; cin >> n; for(i=0;i<n;i++) { cin>>arr[i]; } sort(arr,arr+n); right = n-1; while(left<=right) { if(arr[left] + arr[right] <= w) { left++; right--; } else { right--; } ans++; } cout<<ans<<endl; return 0; }