mod = 10**9+7
def cmb(x, y):
  ret = 1
  for i in range(1, y+1):
    ret = (ret * (x+1-i)) % mod
    ret = (ret * pow(i, mod-2, mod)) % mod
  return ret

n,a,b = map(int,input().split())
ans = (pow(2,n,mod) - 1 - cmb(n,a) - cmb(n,b)) % mod
print(ans) mod = 10**9+7 mod 10**9+7 10**9 10 9 7 def cmb(x, y):
  ret = 1
  for i in range(1, y+1):
    ret = (ret * (x+1-i)) % mod
    ret = (ret * pow(i, mod-2, mod)) % mod
  return ret cmb ret = 1 ret 1 for i in range(1, y+1):
    ret = (ret * (x+1-i)) % mod
    ret = (ret * pow(i, mod-2, mod)) % mod
   i range(1, y+1) range 1 y+1 y 1 ret = (ret * (x+1-i)) % mod ret (ret * (x+1-i)) % mod ret * (x+1-i) ret x+1-i x+1 x 1 i mod ret = (ret * pow(i, mod-2, mod)) % mod ret (ret * pow(i, mod-2, mod)) % mod ret * pow(i, mod-2, mod) ret pow(i, mod-2, mod) pow i mod-2 mod 2 mod mod return ret ret x x y y n,a,b = map(int,input().split()) n map(int,input().split()) map int input().split() ().split () input split a b ans = (pow(2,n,mod) - 1 - cmb(n,a) - cmb(n,b)) % mod ans (pow(2,n,mod) - 1 - cmb(n,a) - cmb(n,b)) % mod pow(2,n,mod) - 1 - cmb(n,a) - cmb(n,b) pow(2,n,mod) - 1 - cmb(n,a) pow(2,n,mod) - 1 pow(2,n,mod) pow 2 n mod 1 cmb(n,a) cmb n a cmb(n,b) cmb n b mod print(ans) print ans n,a,b = map(int,input().split()) map(int,input().split()) n ans = (pow(2,n,mod) - 1 - cmb(n,a) - cmb(n,b)) % mod (pow(2,n,mod) - 1 - cmb(n,a) - cmb(n,b)) % mod ans mod = 10**9+7 10**9+7 mod b = map(int,input().split()) map(int,input().split()) b a,b = map(int,input().split()) map(int,input().split()) a def cmb(x, y):
  ret = 1
  for i in range(1, y+1):
    ret = (ret * (x+1-i)) % mod
    ret = (ret * pow(i, mod-2, mod)) % mod
  return ret def cmb(x, y):
  ret = 1
  for i in range(1, y+1):
    ret = (ret * (x+1-i)) % mod
    ret = (ret * pow(i, mod-2, mod)) % mod
  return ret cmb
mod = 10**9+7
def cmb(x, y):
  ret = 1
  for i in range(1, y+1):
    ret = (ret * (x+1-i)) % mod
    ret = (ret * pow(i, mod-2, mod)) % mod
  return ret

n,a,b = map(int,input().split())
ans = (pow(2,n,mod) - 1 - cmb(n,a) - cmb(n,b)) % mod
print(ans)