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

def modinv(a, mod=10**9+7):
    return pow(a, mod-2, mod)

def mod_comb_count(n, r, mod):
    r = min(r, n-r)
    res = 1
    for i in range(r):
        res = res * (n - i) * modinv(i+1, mod) % mod
    return res

mod=10**9+7
print((2*mod+(pow(2,n,mod)-1)-mod_comb_count(n,a,mod)-mod_comb_count(n,b,mod))%mod) n,a,b=map(int,input().split()) n map(int,input().split()) map int input().split() ().split () input split a b def modinv(a, mod=10**9+7):
    return pow(a, mod-2, mod) modinv return pow(a, mod-2, mod) pow(a, mod-2, mod) pow a mod-2 mod 2 mod a a mod=10**9+7 mod 10**9+7 10**9 10 9 7 def mod_comb_count(n, r, mod):
    r = min(r, n-r)
    res = 1
    for i in range(r):
        res = res * (n - i) * modinv(i+1, mod) % mod
    return res mod_comb_count r = min(r, n-r) r min(r, n-r) min r n-r n r res = 1 res 1 for i in range(r):
        res = res * (n - i) * modinv(i+1, mod) % mod
     i range(r) range r res = res * (n - i) * modinv(i+1, mod) % mod res res * (n - i) * modinv(i+1, mod) % mod res * (n - i) * modinv(i+1, mod) res * (n - i) res n - i n i modinv(i+1, mod) modinv i+1 i 1 mod mod return res res n n r r mod mod mod=10**9+7 mod 10**9+7 10**9 10 9 7 print((2*mod+(pow(2,n,mod)-1)-mod_comb_count(n,a,mod)-mod_comb_count(n,b,mod))%mod) print (2*mod+(pow(2,n,mod)-1)-mod_comb_count(n,a,mod)-mod_comb_count(n,b,mod))%mod 2*mod+(pow(2,n,mod)-1)-mod_comb_count(n,a,mod)-mod_comb_count(n,b,mod) 2*mod+(pow(2,n,mod)-1)-mod_comb_count(n,a,mod) 2*mod+(pow(2,n,mod)-1) 2*mod 2 mod pow(2,n,mod)-1 pow(2,n,mod) pow 2 n mod 1 mod_comb_count(n,a,mod) mod_comb_count n a mod mod_comb_count(n,b,mod) mod_comb_count n b mod mod a,b=map(int,input().split()) map(int,input().split()) a n,a,b=map(int,input().split()) map(int,input().split()) n def modinv(a, mod=10**9+7):
    return pow(a, mod-2, mod) def modinv(a, mod=10**9+7):
    return pow(a, mod-2, mod) modinv mod=10**9+7 10**9+7 mod b=map(int,input().split()) map(int,input().split()) b def mod_comb_count(n, r, mod):
    r = min(r, n-r)
    res = 1
    for i in range(r):
        res = res * (n - i) * modinv(i+1, mod) % mod
    return res def mod_comb_count(n, r, mod):
    r = min(r, n-r)
    res = 1
    for i in range(r):
        res = res * (n - i) * modinv(i+1, mod) % mod
    return res mod_comb_count
n,a,b=map(int,input().split())

def modinv(a, mod=10**9+7):
    return pow(a, mod-2, mod)

def mod_comb_count(n, r, mod):
    r = min(r, n-r)
    res = 1
    for i in range(r):
        res = res * (n - i) * modinv(i+1, mod) % mod
    return res

mod=10**9+7
print((2*mod+(pow(2,n,mod)-1)-mod_comb_count(n,a,mod)-mod_comb_count(n,b,mod))%mod)
