import sequtils,algorithm,math,strutils
template times*(n:int,body) = (for _ in 0..<n: body)
template `max=`*(x,y) = x = max(x,y)
template `min=`*(x,y) = x = min(x,y)

const MOD = 1_000_000_007
proc combinationWithMod(n,k:int):int = # nCk を剰余ありで
  result = 1
  let x = k.max(n - k)
  let y = k.min(n - k)
  var req = 1
  for i in 1..y: req *= i
  for i in 1..y:
    var m = n+1-i
    let g = m.gcd(req)
    m = m div g
    req = req div g
    result = (result * m) mod MOD


proc getchar_unlocked():char {. importc:"getchar_unlocked",header: "<stdio.h>" .}
proc scan(): int =
  while true:
    let k = getchar_unlocked()
    if k < '0': break
    result = 10 * result + k.ord - '0'.ord

let m = scan()
let H = stdin.readLine().split().map(parseInt)
if H.len == 1 :
  if H[0] == 0: quit "1",0
let n = m - (H.sum() - H.len)
let h = H.len()
let k = n - (h + h - 1)
if k < 0: quit "NA",0
if k == 0 : quit "1",0
# h箇所にk個入れる組み合わせ
echo (h+k).combinationWithMod(h)