MOD = pow(10, 9) + 7

def modinv(a, mod):
    return pow(a, mod - 2, mod) % mod

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

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

ans = (pow(2, n, MOD) - 1 - comb(n, a, MOD) - comb(n, b, MOD)) % MOD

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

def modinv(a, mod):
    return pow(a, mod - 2, mod) % mod

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

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

ans = (pow(2, n, MOD) - 1 - comb(n, a, MOD) - comb(n, b, MOD)) % MOD

print(ans)
