import java.io.*;
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        long m = sc.nextLong();
        HashMap<Long, Integer> counts = new HashMap<>();
        for (int i = 0; i < n; i++) {
            long mod = sc.nextLong() % m;
            counts.put(mod, counts.getOrDefault(mod, 0) + 1);
        }
        int ans = 0;
        for (long x : counts.keySet()) {
            if (x == 0) {
                ans += 2;
            } else if (x * 2 == m) {
                ans += 2;
            } else {
                if (counts.containsKey(m - x)) {
                    ans += Math.max(counts.get(x), counts.get(m - x));
                } else {
                    ans += counts.get(x) * 2;
                }
            }
        }
        System.out.println(ans / 2);
    }
}
    
class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    StringBuilder sb = new StringBuilder();
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public String next() throws Exception {
        while (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
    
}