use std;
//proconio
macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut iter = $s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
    ($($r:tt)*) => {
        let mut s = {
            use std::io::Read;
            let mut s = String::new();
            std::io::stdin().read_to_string(&mut s).unwrap();
            s
        };
        let mut iter = s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
}

macro_rules! input_inner {
    ($iter:expr) => {};
    ($iter:expr, ) => {};

    ($iter:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($iter, $t);
        input_inner!{$iter $($r)*}
    };
}

macro_rules! read_value {
    ($iter:expr, ( $($t:tt),* )) => {
        ( $(read_value!($iter, $t)),* )
    };

    ($iter:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($iter, $t)).collect::<Vec<_>>()
    };

    ($iter:expr, chars) => {
        read_value!($iter, String).chars().collect::<Vec<char>>()
    };

    ($iter:expr, usize1) => {
        read_value!($iter, usize) - 1
    };

    ($iter:expr, $t:ty) => {
        $iter.next().unwrap().parse::<$t>().expect("Parse error")
    };
}
fn main() {
    input!{
        n:usize,m:i64,a:[i64;n],
    }

    let mut ans:i64=0;
    let mut cnt:i64=0;
    let mut flag:bool = true;
    let mut memo: std::collections::HashMap<i64,i64>  = std::collections::HashMap::new();
    for t in &a{
        if t%m==0{
            if flag {
                ans+=1;
            flag=false;
            }
            continue;
        }
        *memo.entry(t%m).or_default()+=1_i64;
    }

    let mut ans_memo=vec![];
    for (&key,&val) in memo.iter(){
        let mut rem = m-key;
        if rem==key{
            ans_memo.push(val);
            continue;
        }
        if memo.get(&rem) != None {
            let mut  vval = *memo.get(&rem).unwrap();
            if val>vval{
                ans_memo.push(val)
            }
            else if val == vval{
                if key<rem{
                    ans_memo.push(val);
                }
            }
        }else{
            ans_memo.push(val);
        }
    }    
    ans_memo.sort();
    // dbg!(&ans_memo);
    while ans_memo.len()>0{
        let mut t = ans_memo.pop();
        ans+=t.unwrap();
        cnt+=1;
        if cnt==(n as i64-1)/2{
            break;
        }
    
    }
    println!("{}", ans)



}