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

def cmb(n, r):
  # 分子(n*(n-1)*...*(n-r+1))
  nume = 1
  for i in range(n-r+1, n+1):
    nume = nume * i % p
  # 分母（1*2*...*r）
  deno = 1
  for j in range(1, r+1):
    deno = deno * j % p
    d = pow(deno, p-2, p)
  return nume * d

nca = cmb(n, a)
ncb = cmb(n, b)
res = pow(2, n, p) - nca - ncb - 1
print(res%p) n,a,b=map(int,input().split()) n map(int,input().split()) map int input().split() ().split () input split a b p=10**9+7 p 10**9+7 10**9 10 9 7 def cmb(n, r):
  # 分子(n*(n-1)*...*(n-r+1))
  nume = 1
  for i in range(n-r+1, n+1):
    nume = nume * i % p
  # 分母（1*2*...*r）
  deno = 1
  for j in range(1, r+1):
    deno = deno * j % p
    d = pow(deno, p-2, p)
  return nume * d cmb nume = 1 nume 1 for i in range(n-r+1, n+1):
    nume = nume * i % p
  # 分母（1*2*...*r）
   i range(n-r+1, n+1) range n-r+1 n-r n r 1 n+1 n 1 nume = nume * i % p nume nume * i % p nume * i nume i p deno = 1 deno 1 for j in range(1, r+1):
    deno = deno * j % p
    d = pow(deno, p-2, p)
   j range(1, r+1) range 1 r+1 r 1 deno = deno * j % p deno deno * j % p deno * j deno j p d = pow(deno, p-2, p) d pow(deno, p-2, p) pow deno p-2 p 2 p return nume * d nume * d nume d n n r r nca = cmb(n, a) nca cmb(n, a) cmb n a ncb = cmb(n, b) ncb cmb(n, b) cmb n b res = pow(2, n, p) - nca - ncb - 1 res pow(2, n, p) - nca - ncb - 1 pow(2, n, p) - nca - ncb pow(2, n, p) - nca pow(2, n, p) pow 2 n p nca ncb 1 print(res%p) print res%p res p ncb = cmb(n, b) cmb(n, b) ncb n,a,b=map(int,input().split()) map(int,input().split()) n def cmb(n, r):
  # 分子(n*(n-1)*...*(n-r+1))
  nume = 1
  for i in range(n-r+1, n+1):
    nume = nume * i % p
  # 分母（1*2*...*r）
  deno = 1
  for j in range(1, r+1):
    deno = deno * j % p
    d = pow(deno, p-2, p)
  return nume * d def cmb(n, r):
  # 分子(n*(n-1)*...*(n-r+1))
  nume = 1
  for i in range(n-r+1, n+1):
    nume = nume * i % p
  # 分母（1*2*...*r）
  deno = 1
  for j in range(1, r+1):
    deno = deno * j % p
    d = pow(deno, p-2, p)
  return nume * d cmb nca = cmb(n, a) cmb(n, a) nca p=10**9+7 10**9+7 p res = pow(2, n, p) - nca - ncb - 1 pow(2, n, p) - nca - ncb - 1 res a,b=map(int,input().split()) map(int,input().split()) a b=map(int,input().split()) map(int,input().split()) b
n,a,b=map(int,input().split())
p=10**9+7

def cmb(n, r):
  # 分子(n*(n-1)*...*(n-r+1))
  nume = 1
  for i in range(n-r+1, n+1):
    nume = nume * i % p
  # 分母（1*2*...*r）
  deno = 1
  for j in range(1, r+1):
    deno = deno * j % p
    d = pow(deno, p-2, p)
  return nume * d

nca = cmb(n, a)
ncb = cmb(n, b)
res = pow(2, n, p) - nca - ncb - 1
print(res%p)