fn main() {
	let mut io = IO::new();
    input!{ from io,
		m: usize,
		n: usize,
		c: [usize; n]
    }
	let mut dp = vec![std::i64::MIN; m+1];
	dp[0] = 0;
	for &x in &c {
		for i in x..=m {
			dp[i] = dp[i].max(dp[i-x] + 1);
		}
	}
	let sieve = atkin_sieve(m as usize);
	let mut ans = *dp.iter().max().unwrap();
	for x in sieve.into_iter().map(|x| x as usize) {
		if dp[m-x] > 0 {
			ans += dp[m-x];
		}
	}
    io.println(ans);
}

pub fn atkin_sieve(n: usize) -> Vec<i64> {
    let mut sieve = BitSet::new(n+1);
    let lim = (n as f64).sqrt() as usize + 1;

    for z in (1..6).step_by(4) {
        for y in (z..lim).step_by(6) {
            for x in 1..lim {
                if 4 * x * x + y * y > n { break; }
                sieve.flip(4 * x * x + y * y);
            }
            for x in (y+1..lim).step_by(2) {
                if 3 * x * x - y * y > n { break; }
                sieve.flip(3 * x * x - y * y);
            }
        }
    }

    for z in (2..5).step_by(2) {
        for y in (z..lim).step_by(6) {
            for x in (1..lim).step_by(2) {
                if 3 * x * x + y * y > n { break; }
                sieve.flip(3 * x * x + y * y);
            }
            for x in (y+1..lim).step_by(2) {
                if 3 * x * x - y * y > n { break; }
                sieve.flip(3 * x * x - y * y);
            }
        }
    }

    for z in 1..3 {
        for y in (3..lim).step_by(6) {
            for x in (z..lim).step_by(3) {
                if 4 * x * x + y * y > n { break; }
                sieve.flip(4 * x * x + y * y);
            }
        }
    }

    for i in 5..lim {
        if sieve.access(i) {
            for j in (i*i..n+1).step_by(i*i) {
                sieve.set(j, false);
            }
        }
    }
    sieve.set(2, true);
    sieve.set(3, true);
    sieve.collect().into_iter().map(|x| x as i64).collect()
}

use std::ops::{Shl, Shr, BitAnd, BitOr, BitXor, Not};

#[derive(Clone)]
pub struct BitSet {
    data: Vec<u32>,
    size: usize
}

impl BitSet {
    pub fn new(size: usize) -> Self {
        let data = vec![0; (size >> 5) + 1];
        BitSet{ data, size }
    }

    pub fn fill(&mut self) {
        self.data.iter_mut().for_each(|x| *x = 0xffffffff );
    }

    pub fn access(&self, pos: usize) -> bool {
        (self.data[pos >> 5] >> (pos & 31)) & 1 == 1
    }

    pub fn set(&mut self, pos: usize, v: bool) {
        if v {
            self.data[pos >> 5] |= 1 << (pos & 31);
        } else {
            self.data[pos >> 5] &= !(1 << (pos & 31));
        }
    }

    pub fn flip(&mut self, pos: usize) {
        self.data[pos >> 5] ^= 1 << (pos & 31);
    }

    pub fn collect(&self) -> Vec<u64> {
        (0..self.size)
        .filter(|&i| self.access(i))
        .map(|x| x as u64)
        .collect::<Vec<u64>>()
    }

    fn resize(&mut self, l: usize) {
        if self.size > l { return; }
        self.data.resize((l >> 5) + 1, 0);
        self.size = l;
    }
}

impl BitAnd for BitSet {
    type Output = Self;
    fn bitand(mut self, rhs: Self) -> Self {
        let m = std::cmp::max(self.size, rhs.size);
        self.resize(m);
        for (u, v) in self.data.iter_mut().zip(rhs.data.iter()) {
            *u &= v;
        }
        self
    }
}

impl BitOr for BitSet {
    type Output = Self;
    fn bitor(mut self, rhs: Self) -> Self {
        let m = std::cmp::max(self.size, rhs.size);
        self.resize(m);
        for (u, v) in self.data.iter_mut().zip(rhs.data.iter()) {
            *u |= v;
        }
        self
    }
}

impl BitXor for BitSet {
    type Output = Self;
    fn bitxor(mut self, rhs: Self) -> Self {
        let m = std::cmp::max(self.size, rhs.size);
        self.resize(m);
        for (u, v) in self.data.iter_mut().zip(rhs.data.iter()) {
            *u ^= v;
        }
        self
    }
}

impl Not for BitSet {
    type Output = Self;
    fn not(mut self) -> Self {
        for u in self.data.iter_mut() {
            *u = !*u;
        }
        self
    }
}

impl Shr<usize> for BitSet {
    type Output = Self;
    fn shr(mut self, rhs: usize) -> Self::Output {
        let big = rhs >> 5;
        let sml = (rhs & 31) as u32;
        let mask = (1 << sml) - 1;
        for i in 0..self.data.len() {
            self.data[i] = if i + big < self.data.len() {
                self.data[i+big]
            } else {
                0
            };
        }
        let mut r = 0;
        for i in (0..self.data.len()).rev() {
            let u = self.data[i];
            self.data[i] = (u & !mask | r).rotate_right(sml);
            r = u & mask;
        }
        self
    }
}

impl Shl<usize> for BitSet {
    type Output = Self;
    fn shl(mut self, rhs: usize) -> Self::Output {
        let n = self.data.len();
        let big = rhs >> 5;
        let sml = (rhs & 31) as u32;
        let mask = (1 << sml) - 1;
        for i in (0..n).rev() {
            self.data[i] = if i >= big {
                self.data[i-big]
            } else {
                0
            };
        }
        let mut r = 0;
        for i in 0..n {
            let u = self.data[i].rotate_left(sml);
            self.data[i] = u & !mask | r;
            r = u & mask;
        }
        self.data[n-1] &= (1 << (self.size & 31)) - 1;
        self
    }
}

// ------------ io module start ------------
use std::io::{stdout, BufWriter, Read, StdoutLock, Write};

pub struct IO {
	iter: std::str::SplitAsciiWhitespace<'static>,
	buf: BufWriter<StdoutLock<'static>>,
}

impl IO {
	pub fn new() -> Self {
		let mut input = String::new();
		std::io::stdin().read_to_string(&mut input).unwrap();
		let input = Box::leak(input.into_boxed_str());
		let out = Box::new(stdout());
		IO {
			iter: input.split_ascii_whitespace(),
			buf: BufWriter::new(Box::leak(out).lock()),
		}
	}
	fn scan_str(&mut self) -> &'static str {
		self.iter.next().unwrap()
	}
	pub fn scan<T: Scan>(&mut self) -> <T as Scan>::Output {
		<T as Scan>::scan(self)
	}
	pub fn scan_vec<T: Scan>(&mut self, n: usize) -> Vec<<T as Scan>::Output> {
		(0..n).map(|_| self.scan::<T>()).collect()
	}
	pub fn print<T: Print>(&mut self, x: T) {
		<T as Print>::print(self, x);
	}
	pub fn println<T: Print>(&mut self, x: T) {
		self.print(x);
		self.print("\n");
	}
	pub fn iterln<T: Print, I: Iterator<Item = T>>(&mut self, mut iter: I, delim: &str) {
		if let Some(v) = iter.next() {
			self.print(v);
			for v in iter {
				self.print(delim);
				self.print(v);
			}
		}
		self.print("\n");
	}
	pub fn flush(&mut self) {
		self.buf.flush().unwrap();
	}
}

impl Default for IO {
	fn default() -> Self {
		Self::new()
	}
}

pub trait Scan {
	type Output;
	fn scan(io: &mut IO) -> Self::Output;
}

macro_rules! impl_scan {
	($($t:tt),*) => {
		$(
			impl Scan for $t {
				type Output = Self;
				fn scan(s: &mut IO) -> Self::Output {
					s.scan_str().parse().unwrap()
				}
			}
		)*
	};
}

impl_scan!(i16, i32, i64, isize, u16, u32, u64, usize, String, f32, f64);

pub enum Bytes {}
impl Scan for Bytes {
	type Output = &'static [u8];
	fn scan(s: &mut IO) -> Self::Output {
		s.scan_str().as_bytes()
	}
}

pub enum Chars {}
impl Scan for Chars {
	type Output = Vec<char>;
	fn scan(s: &mut IO) -> Self::Output {
		s.scan_str().chars().collect()
	}
}

pub enum Usize1 {}
impl Scan for Usize1 {
	type Output = usize;
	fn scan(s: &mut IO) -> Self::Output {
		s.scan::<usize>().wrapping_sub(1)
	}
}

impl<T: Scan, U: Scan> Scan for (T, U) {
	type Output = (T::Output, U::Output);
	fn scan(s: &mut IO) -> Self::Output {
		(T::scan(s), U::scan(s))
	}
}

impl<T: Scan, U: Scan, V: Scan> Scan for (T, U, V) {
	type Output = (T::Output, U::Output, V::Output);
	fn scan(s: &mut IO) -> Self::Output {
		(T::scan(s), U::scan(s), V::scan(s))
	}
}

impl<T: Scan, U: Scan, V: Scan, W: Scan> Scan for (T, U, V, W) {
	type Output = (T::Output, U::Output, V::Output, W::Output);
	fn scan(s: &mut IO) -> Self::Output {
		(T::scan(s), U::scan(s), V::scan(s), W::scan(s))
	}
}

pub trait Print {
	fn print(w: &mut IO, x: Self);
}

macro_rules! impl_print_int {
	($($t:ty),*) => {
		$(
			impl Print for $t {
				fn print(w: &mut IO, x: Self) {
					w.buf.write_all(x.to_string().as_bytes()).unwrap();
				}
			}
		)*
	};
}

impl_print_int!(i16, i32, i64, isize, u16, u32, u64, usize, f32, f64);

impl Print for u8 {
	fn print(w: &mut IO, x: Self) {
		w.buf.write_all(&[x]).unwrap();
	}
}

impl Print for &[u8] {
	fn print(w: &mut IO, x: Self) {
		w.buf.write_all(x).unwrap();
	}
}

impl Print for &str {
	fn print(w: &mut IO, x: Self) {
		w.print(x.as_bytes());
	}
}

impl Print for String {
	fn print(w: &mut IO, x: Self) {
		w.print(x.as_bytes());
	}
}

impl<T: Print, U: Print> Print for (T, U) {
	fn print(w: &mut IO, (x, y): Self) {
		w.print(x);
		w.print(" ");
		w.print(y);
	}
}

impl<T: Print, U: Print, V: Print> Print for (T, U, V) {
	fn print(w: &mut IO, (x, y, z): Self) {
		w.print(x);
		w.print(" ");
		w.print(y);
		w.print(" ");
		w.print(z);
	}
}

mod neboccoio_macro {
	#[macro_export]
	macro_rules! input {
		(@start $io:tt @read @rest) => {};

		(@start $io:tt @read @rest, $($rest: tt)*) => {
			input!(@start $io @read @rest $($rest)*)
		};

		(@start $io:tt @read @rest mut $($rest:tt)*) => {
			input!(@start $io @read @mut [mut] @rest $($rest)*)
		};

		(@start $io:tt @read @rest $($rest:tt)*) => {
			input!(@start $io @read @mut [] @rest $($rest)*)
		};

		(@start $io:tt @read @mut [$($mut:tt)?] @rest $var:tt: [$kind:tt; $len:expr] $($rest:tt)*) => {
			let $($mut)* $var = $io.scan_vec::<$kind>($len);
			input!(@start $io @read @rest $($rest)*)
		};

		(@start $io:tt @read @mut [$($mut:tt)?] @rest $var:tt: $kind:tt $($rest:tt)*) => {
			let $($mut)* $var = $io.scan::<$kind>();
			input!(@start $io @read @rest $($rest)*)
		};

		(from $io:tt $($rest:tt)*) => {
			input!(@start $io @read @rest $($rest)*)
		};
	}
}

// ------------ io module end ------------