
MOD = 10 ** 9 + 7


def comb(n, k):
    if n < k or k < 0:
        return 0

    res = 1
    for i in range(1, k + 1):
        res = res * (n - i + 1) % MOD
        res = res * pow(i, MOD - 2, MOD) % MOD
    return res


N, A, B = map(int, input().split())
x1 = comb(N, A)
x2 = comb(N, B)
print((pow(2, N, MOD) - 1 - x1 - x2) % MOD) MOD = 10 ** 9 + 7 MOD 10 ** 9 + 7 10 ** 9 10 9 7 def comb(n, k):
    if n < k or k < 0:
        return 0

    res = 1
    for i in range(1, k + 1):
        res = res * (n - i + 1) % MOD
        res = res * pow(i, MOD - 2, MOD) % MOD
    return res comb if n < k or k < 0:
        return 0

     n < k or k < 0 n < k n k k < 0 k 0 return 0 0 res = 1 res 1 for i in range(1, k + 1):
        res = res * (n - i + 1) % MOD
        res = res * pow(i, MOD - 2, MOD) % MOD
     i range(1, k + 1) range 1 k + 1 k 1 res = res * (n - i + 1) % MOD res res * (n - i + 1) % MOD res * (n - i + 1) res n - i + 1 n - i n i 1 MOD res = res * pow(i, MOD - 2, MOD) % MOD res res * pow(i, MOD - 2, MOD) % MOD res * pow(i, MOD - 2, MOD) res pow(i, MOD - 2, MOD) pow i MOD - 2 MOD 2 MOD MOD return res res n n k k N, A, B = map(int, input().split()) N map(int, input().split()) map int input().split() ().split () input split A B x1 = comb(N, A) x1 comb(N, A) comb N A x2 = comb(N, B) x2 comb(N, B) comb N B print((pow(2, N, MOD) - 1 - x1 - x2) % MOD) print (pow(2, N, MOD) - 1 - x1 - x2) % MOD pow(2, N, MOD) - 1 - x1 - x2 pow(2, N, MOD) - 1 - x1 pow(2, N, MOD) - 1 pow(2, N, MOD) pow 2 N MOD 1 x1 x2 MOD A, B = map(int, input().split()) map(int, input().split()) A x1 = comb(N, A) comb(N, A) x1 MOD = 10 ** 9 + 7 10 ** 9 + 7 MOD def comb(n, k):
    if n < k or k < 0:
        return 0

    res = 1
    for i in range(1, k + 1):
        res = res * (n - i + 1) % MOD
        res = res * pow(i, MOD - 2, MOD) % MOD
    return res def comb(n, k):
    if n < k or k < 0:
        return 0

    res = 1
    for i in range(1, k + 1):
        res = res * (n - i + 1) % MOD
        res = res * pow(i, MOD - 2, MOD) % MOD
    return res comb B = map(int, input().split()) map(int, input().split()) B x2 = comb(N, B) comb(N, B) x2 N, A, B = map(int, input().split()) map(int, input().split()) N

MOD = 10 ** 9 + 7


def comb(n, k):
    if n < k or k < 0:
        return 0

    res = 1
    for i in range(1, k + 1):
        res = res * (n - i + 1) % MOD
        res = res * pow(i, MOD - 2, MOD) % MOD
    return res


N, A, B = map(int, input().split())
x1 = comb(N, A)
x2 = comb(N, B)
print((pow(2, N, MOD) - 1 - x1 - x2) % MOD)
