from functools import reduce
N,a,b = map(int,input().split())
MOD = 10**9+7
def f(r):
    nPr = reduce(lambda x,y: x * y % MOD,range(N,N-r,-1))
    r_fact = reduce(lambda x,y: x * y % MOD,range(1,r+1))
    return nPr * pow(r_fact,MOD-2,MOD) % MOD
result = pow(2,N,MOD) - f(a) - f(b) - 1
result %= MOD
print(result) 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 f(r):
    nPr = reduce(lambda x,y: x * y % MOD,range(N,N-r,-1))
    r_fact = reduce(lambda x,y: x * y % MOD,range(1,r+1))
    return nPr * pow(r_fact,MOD-2,MOD) % MOD f nPr = reduce(lambda x,y: x * y % MOD,range(N,N-r,-1)) nPr reduce(lambda x,y: x * y % MOD,range(N,N-r,-1)) reduce lambda x,y: x * y % MOD x * y % MOD x * y x y MOD x y range(N,N-r,-1) range N N-r N r -1 r_fact = reduce(lambda x,y: x * y % MOD,range(1,r+1)) r_fact reduce(lambda x,y: x * y % MOD,range(1,r+1)) reduce lambda x,y: x * y % MOD x * y % MOD x * y x y MOD x y range(1,r+1) range 1 r+1 r 1 return nPr * pow(r_fact,MOD-2,MOD) % MOD nPr * pow(r_fact,MOD-2,MOD) % MOD nPr * pow(r_fact,MOD-2,MOD) nPr pow(r_fact,MOD-2,MOD) pow r_fact MOD-2 MOD 2 MOD MOD r r result = pow(2,N,MOD) - f(a) - f(b) - 1 result pow(2,N,MOD) - f(a) - f(b) - 1 pow(2,N,MOD) - f(a) - f(b) pow(2,N,MOD) - f(a) pow(2,N,MOD) pow 2 N MOD f(a) f a f(b) f b 1 result %= MOD result MOD print(result) print result b = map(int,input().split()) map(int,input().split()) b MOD = 10**9+7 10**9+7 MOD result = pow(2,N,MOD) - f(a) - f(b) - 1 pow(2,N,MOD) - f(a) - f(b) - 1 result N,a,b = map(int,input().split()) map(int,input().split()) N result %= MOD MOD result a,b = map(int,input().split()) map(int,input().split()) a def f(r):
    nPr = reduce(lambda x,y: x * y % MOD,range(N,N-r,-1))
    r_fact = reduce(lambda x,y: x * y % MOD,range(1,r+1))
    return nPr * pow(r_fact,MOD-2,MOD) % MOD def f(r):
    nPr = reduce(lambda x,y: x * y % MOD,range(N,N-r,-1))
    r_fact = reduce(lambda x,y: x * y % MOD,range(1,r+1))
    return nPr * pow(r_fact,MOD-2,MOD) % MOD f
from functools import reduce
N,a,b = map(int,input().split())
MOD = 10**9+7
def f(r):
    nPr = reduce(lambda x,y: x * y % MOD,range(N,N-r,-1))
    r_fact = reduce(lambda x,y: x * y % MOD,range(1,r+1))
    return nPr * pow(r_fact,MOD-2,MOD) % MOD
result = pow(2,N,MOD) - f(a) - f(b) - 1
result %= MOD
print(result)
