n,a,b = map(int,input().split())
m = 10**9+7

def nCr(n_, r_, m_):
  c = min(r_ , n_ - r_)
  bunshi = 1
  bunbo = 1
  for i in range(1,c+1):
    bunshi = bunshi * (n_+1-i) % m_
    bunbo = bunbo * i % m_
  return bunshi * pow(bunbo, m_-2, m_) % m_


ans = pow(2,n,m)-1
ans -= nCr(n,a,m)
ans %= m
ans -= nCr(n,b,m)
ans %= m
print(ans) n,a,b = map(int,input().split()) n map(int,input().split()) map int input().split() ().split () input split a b m = 10**9+7 m 10**9+7 10**9 10 9 7 def nCr(n_, r_, m_):
  c = min(r_ , n_ - r_)
  bunshi = 1
  bunbo = 1
  for i in range(1,c+1):
    bunshi = bunshi * (n_+1-i) % m_
    bunbo = bunbo * i % m_
  return bunshi * pow(bunbo, m_-2, m_) % m_ nCr c = min(r_ , n_ - r_) c min(r_ , n_ - r_) min r_ n_ - r_ n_ r_ bunshi = 1 bunshi 1 bunbo = 1 bunbo 1 for i in range(1,c+1):
    bunshi = bunshi * (n_+1-i) % m_
    bunbo = bunbo * i % m_
   i range(1,c+1) range 1 c+1 c 1 bunshi = bunshi * (n_+1-i) % m_ bunshi bunshi * (n_+1-i) % m_ bunshi * (n_+1-i) bunshi n_+1-i n_+1 n_ 1 i m_ bunbo = bunbo * i % m_ bunbo bunbo * i % m_ bunbo * i bunbo i m_ return bunshi * pow(bunbo, m_-2, m_) % m_ bunshi * pow(bunbo, m_-2, m_) % m_ bunshi * pow(bunbo, m_-2, m_) bunshi pow(bunbo, m_-2, m_) pow bunbo m_-2 m_ 2 m_ m_ n_ n_ r_ r_ m_ m_ ans = pow(2,n,m)-1 ans pow(2,n,m)-1 pow(2,n,m) pow 2 n m 1 ans -= nCr(n,a,m) ans nCr(n,a,m) nCr n a m ans %= m ans m ans -= nCr(n,b,m) ans nCr(n,b,m) nCr n b m ans %= m ans m print(ans) print ans a,b = map(int,input().split()) map(int,input().split()) a ans %= m m ans b = map(int,input().split()) map(int,input().split()) b m = 10**9+7 10**9+7 m ans -= nCr(n,a,m) nCr(n,a,m) ans ans -= nCr(n,b,m) nCr(n,b,m) ans n,a,b = map(int,input().split()) map(int,input().split()) n ans = pow(2,n,m)-1 pow(2,n,m)-1 ans def nCr(n_, r_, m_):
  c = min(r_ , n_ - r_)
  bunshi = 1
  bunbo = 1
  for i in range(1,c+1):
    bunshi = bunshi * (n_+1-i) % m_
    bunbo = bunbo * i % m_
  return bunshi * pow(bunbo, m_-2, m_) % m_ def nCr(n_, r_, m_):
  c = min(r_ , n_ - r_)
  bunshi = 1
  bunbo = 1
  for i in range(1,c+1):
    bunshi = bunshi * (n_+1-i) % m_
    bunbo = bunbo * i % m_
  return bunshi * pow(bunbo, m_-2, m_) % m_ nCr ans %= m m ans
n,a,b = map(int,input().split())
m = 10**9+7

def nCr(n_, r_, m_):
  c = min(r_ , n_ - r_)
  bunshi = 1
  bunbo = 1
  for i in range(1,c+1):
    bunshi = bunshi * (n_+1-i) % m_
    bunbo = bunbo * i % m_
  return bunshi * pow(bunbo, m_-2, m_) % m_


ans = pow(2,n,m)-1
ans -= nCr(n,a,m)
ans %= m
ans -= nCr(n,b,m)
ans %= m
print(ans)