import std.algorithm, std.conv, std.range, std.stdio, std.string;

const mod = 10 ^^ 9 + 7;
alias FactorRing!mod mint;

void main()
{
  auto m = readln.chomp.to!int;
  auto h = readln.split.to!(int[]), k = h.length.to!int;

  if (h[0] == 0) {
    writeln(1);
    return;
  }

  auto n = m - h.sum - (k - 1);
  if (n < 0) {
    writeln("NA");
    return;
  }

  auto r = mint(1);
  foreach (i; n+1..n+k+1) r *= i;
  foreach (i; 1..k+1) r *= mint(i).inv;

  writeln(r);
}

struct FactorRing(int m, bool pos = false)
{
  long v;

  @property int toInt() { return v.to!int; }
  alias toInt this;

  this(T)(T _v) { v = mod(_v); }

  ref FactorRing!(m, pos) opAssign(int _v)
  {
    v = mod(_v);
    return this;
  }

  pure auto mod(long _v) const
  {
    static if (pos) return _v % m;
    else return (_v % m + m) % m;
  }

  pure auto opBinary(string op: "+")(long rhs) const { return FactorRing!(m, pos)(v + rhs); }
  pure auto opBinary(string op: "-")(long rhs) const { return FactorRing!(m, pos)(v - rhs); }
  pure auto opBinary(string op: "*")(long rhs) const { return FactorRing!(m, pos)(v * rhs); }

  pure auto opBinary(string op)(FactorRing!(m, pos) rhs) const
    if (op == "+" || op == "-" || op == "*") { return opBinary!op(rhs.v); }

  auto opOpAssign(string op: "+")(long rhs) { v = mod(v + rhs); }
  auto opOpAssign(string op: "-")(long rhs) { v = mod(v - rhs); }
  auto opOpAssign(string op: "*")(long rhs) { v = mod(v * rhs); }

  auto opOpAssign(string op)(FactorRing!(m, pos) rhs)
    if (op == "+" || op == "-" || op == "*") { return opOpAssign!op(rhs.v); }

  pure auto inv() const
  {
    int x = v.to!int, a, b;
    exEuclid(x, m, a, b);
    return FactorRing!(m, pos)(a);
  }
}

pure T exEuclid(T)(T a, T b, ref T x, ref T y)
{
  auto g = a;
  x = 1;
  y = 0;
  if (b != 0) {
    g = exEuclid(b, a % b, y, x);
    y -= a / b * x;
  }
  return g;
}