from functools import reduce

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

MOD = 10**9 + 7


def comb(n, r, mod=float("inf")):
    c = 1
    m = 1
    r = min(n - r, r)
    for i in range(r):
        c = c * (n - i) % mod
        m = m * (i + 1) % mod
    return c * pow(m, mod - 2, mod) % mod


print((pow(2, n, MOD) - comb(n, a, MOD) - comb(n, b, MOD) - 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 comb(n, r, mod=float("inf")):
    c = 1
    m = 1
    r = min(n - r, r)
    for i in range(r):
        c = c * (n - i) % mod
        m = m * (i + 1) % mod
    return c * pow(m, mod - 2, mod) % mod comb c = 1 c 1 m = 1 m 1 r = min(n - r, r) r min(n - r, r) min n - r n r r for i in range(r):
        c = c * (n - i) % mod
        m = m * (i + 1) % mod
     i range(r) range r c = c * (n - i) % mod c c * (n - i) % mod c * (n - i) c n - i n i mod m = m * (i + 1) % mod m m * (i + 1) % mod m * (i + 1) m i + 1 i 1 mod 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 r r mod=float("inf") mod float("inf") float "inf" print((pow(2, n, MOD) - comb(n, a, MOD) - comb(n, b, MOD) - 1) % MOD) print (pow(2, n, MOD) - comb(n, a, MOD) - comb(n, b, MOD) - 1) % MOD pow(2, n, MOD) - comb(n, a, MOD) - comb(n, b, MOD) - 1 pow(2, n, MOD) - comb(n, a, MOD) - comb(n, b, MOD) pow(2, n, MOD) - comb(n, a, MOD) pow(2, n, MOD) pow 2 n MOD comb(n, a, MOD) comb n a MOD comb(n, b, MOD) comb n b MOD 1 MOD MOD = 10**9 + 7 10**9 + 7 MOD a, b = map(int, input().split(" ")) map(int, input().split(" ")) a def comb(n, r, mod=float("inf")):
    c = 1
    m = 1
    r = min(n - r, r)
    for i in range(r):
        c = c * (n - i) % mod
        m = m * (i + 1) % mod
    return c * pow(m, mod - 2, mod) % mod def comb(n, r, mod=float("inf")):
    c = 1
    m = 1
    r = min(n - r, r)
    for i in range(r):
        c = c * (n - i) % mod
        m = m * (i + 1) % mod
    return c * pow(m, mod - 2, mod) % mod comb b = map(int, input().split(" ")) map(int, input().split(" ")) b n, a, b = map(int, input().split(" ")) map(int, input().split(" ")) n
from functools import reduce

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

MOD = 10**9 + 7


def comb(n, r, mod=float("inf")):
    c = 1
    m = 1
    r = min(n - r, r)
    for i in range(r):
        c = c * (n - i) % mod
        m = m * (i + 1) % mod
    return c * pow(m, mod - 2, mod) % mod


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