from functools import reduce

n,a,b=map(int,input().split())

mod=10**9+7
def nCk(n,k):
  c=reduce(lambda x,y: x*y%mod, range(n,n-k,-1))
  m=reduce(lambda x,y: x*y%mod, range(1,k+1))
  return c*pow(m,mod-2,mod)%mod

all=pow(2,n,mod)
nCa=nCk(n,a)
nCb=nCk(n,b)

print((all-nCa-nCb-1)%mod) from functools import reduce n,a,b=map(int,input().split()) n map(int,input().split()) map int input().split() ().split () input split a b mod=10**9+7 mod 10**9+7 10**9 10 9 7 def nCk(n,k):
  c=reduce(lambda x,y: x*y%mod, range(n,n-k,-1))
  m=reduce(lambda x,y: x*y%mod, range(1,k+1))
  return c*pow(m,mod-2,mod)%mod nCk c=reduce(lambda x,y: x*y%mod, range(n,n-k,-1)) c reduce(lambda x,y: x*y%mod, range(n,n-k,-1)) reduce lambda x,y: x*y%mod x*y%mod x*y x y mod x y range(n,n-k,-1) range n n-k n k -1 m=reduce(lambda x,y: x*y%mod, range(1,k+1)) m reduce(lambda x,y: x*y%mod, range(1,k+1)) reduce lambda x,y: x*y%mod x*y%mod x*y x y mod x y range(1,k+1) range 1 k+1 k 1 return c*pow(m,mod-2,mod)%mod c*pow(m,mod-2,mod)%mod c*pow(m,mod-2,mod) c pow(m,mod-2,mod) pow m mod-2 mod 2 mod mod n n k k all=pow(2,n,mod) all pow(2,n,mod) pow 2 n mod nCa=nCk(n,a) nCa nCk(n,a) nCk n a nCb=nCk(n,b) nCb nCk(n,b) nCk n b print((all-nCa-nCb-1)%mod) print (all-nCa-nCb-1)%mod all-nCa-nCb-1 all-nCa-nCb all-nCa all nCa nCb 1 mod n,a,b=map(int,input().split()) map(int,input().split()) n a,b=map(int,input().split()) map(int,input().split()) a all=pow(2,n,mod) pow(2,n,mod) all nCa=nCk(n,a) nCk(n,a) nCa nCb=nCk(n,b) nCk(n,b) nCb mod=10**9+7 10**9+7 mod b=map(int,input().split()) map(int,input().split()) b def nCk(n,k):
  c=reduce(lambda x,y: x*y%mod, range(n,n-k,-1))
  m=reduce(lambda x,y: x*y%mod, range(1,k+1))
  return c*pow(m,mod-2,mod)%mod def nCk(n,k):
  c=reduce(lambda x,y: x*y%mod, range(n,n-k,-1))
  m=reduce(lambda x,y: x*y%mod, range(1,k+1))
  return c*pow(m,mod-2,mod)%mod nCk
from functools import reduce

n,a,b=map(int,input().split())

mod=10**9+7
def nCk(n,k):
  c=reduce(lambda x,y: x*y%mod, range(n,n-k,-1))
  m=reduce(lambda x,y: x*y%mod, range(1,k+1))
  return c*pow(m,mod-2,mod)%mod

all=pow(2,n,mod)
nCa=nCk(n,a)
nCb=nCk(n,b)

print((all-nCa-nCb-1)%mod)