#include<bits/stdc++.h>
using namespace std;

int find_max_apples(int max_size_difference, vector<int> apple_sizes) {
    int n = apple_sizes.size();
    sort(apple_sizes.begin(), apple_sizes.end());
    int j = 0, mx = 0;
    for(int i = 0; i < n; i++) {
        while(j < n && apple_sizes[j] - apple_sizes[i] <= max_size_difference) {
            j++;
        }
        mx = max(mx, j- i);
    }
    return mx;
}

int main()
{
    int max_size_difference, n;
    cin >> max_size_difference >> n;
    vector<int> apple_sizes(n);
    for(int i = 0; i < n; i++) {
        cin >> apple_sizes[i];
    }
    cout << find_max_apples(max_size_difference, apple_sizes);
    return 0;
}