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

def modInverse(a,p):
    # Fermat's little theorem, a**(p-1) = 1 mod p
    return pow(a,p-2,p)

def nCr(n,r,p=mod):
    num = 1
    den = 1
    for i in range(r):
        num = (num*(n-i)) % p
        den = (den*(i+1)) % p
    return num*modInverse(den,p)% p

ans = pow(2,n,mod)-1
print((ans-nCr(n,a)-nCr(n,b))%mod) 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 modInverse(a,p):
    # Fermat's little theorem, a**(p-1) = 1 mod p
    return pow(a,p-2,p) modInverse return pow(a,p-2,p) pow(a,p-2,p) pow a p-2 p 2 p a a p p def nCr(n,r,p=mod):
    num = 1
    den = 1
    for i in range(r):
        num = (num*(n-i)) % p
        den = (den*(i+1)) % p
    return num*modInverse(den,p)% p nCr num = 1 num 1 den = 1 den 1 for i in range(r):
        num = (num*(n-i)) % p
        den = (den*(i+1)) % p
     i range(r) range r num = (num*(n-i)) % p num (num*(n-i)) % p num*(n-i) num n-i n i p den = (den*(i+1)) % p den (den*(i+1)) % p den*(i+1) den i+1 i 1 p return num*modInverse(den,p)% p num*modInverse(den,p)% p num*modInverse(den,p) num modInverse(den,p) modInverse den p p n n r r p=mod p mod ans = pow(2,n,mod)-1 ans pow(2,n,mod)-1 pow(2,n,mod) pow 2 n mod 1 print((ans-nCr(n,a)-nCr(n,b))%mod) print (ans-nCr(n,a)-nCr(n,b))%mod ans-nCr(n,a)-nCr(n,b) ans-nCr(n,a) ans nCr(n,a) nCr n a nCr(n,b) nCr n b mod b = map(int,input().split()) map(int,input().split()) b def modInverse(a,p):
    # Fermat's little theorem, a**(p-1) = 1 mod p
    return pow(a,p-2,p) def modInverse(a,p):
    # Fermat's little theorem, a**(p-1) = 1 mod p
    return pow(a,p-2,p) modInverse ans = pow(2,n,mod)-1 pow(2,n,mod)-1 ans a,b = map(int,input().split()) map(int,input().split()) a def nCr(n,r,p=mod):
    num = 1
    den = 1
    for i in range(r):
        num = (num*(n-i)) % p
        den = (den*(i+1)) % p
    return num*modInverse(den,p)% p def nCr(n,r,p=mod):
    num = 1
    den = 1
    for i in range(r):
        num = (num*(n-i)) % p
        den = (den*(i+1)) % p
    return num*modInverse(den,p)% p nCr n,a,b = map(int,input().split()) map(int,input().split()) n mod = 10**9+7 10**9+7 mod
n,a,b = map(int,input().split())
mod = 10**9+7

def modInverse(a,p):
    # Fermat's little theorem, a**(p-1) = 1 mod p
    return pow(a,p-2,p)

def nCr(n,r,p=mod):
    num = 1
    den = 1
    for i in range(r):
        num = (num*(n-i)) % p
        den = (den*(i+1)) % p
    return num*modInverse(den,p)% p

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