class Combination:

    """階乗とその逆元のテーブルをO(N)で事前作成し、組み合わせの計算をO(1)で行う"""

    def __init__(self, n, MOD):

        self.fact = [1]

        for i in range(1, n + 1):

            self.fact.append(self.fact[-1] * i % MOD)

        self.inv_fact = [0] * (n + 1)

        self.inv_fact[n] = pow(self.fact[n], MOD - 2, MOD)

        for i in reversed(list(range(n))):

            self.inv_fact[i] = self.inv_fact[i + 1] * (i + 1) % MOD

        self.MOD = MOD



    def factorial(self, k):

        """k!を求める O(1)"""

        return self.fact[k]



    def inverse_factorial(self, k):

        """k!の逆元を求める O(1)"""

        return self.inv_fact[k]



    def permutation(self, k, r):

        """kPrを求める O(1)"""

        if k < r:

            return 0

        return (self.fact[k] * self.inv_fact[k - r]) % self.MOD



    def combination(self, k, r):

        """kCrを求める O(1)"""

        if k < r:

            return 0

        return (self.fact[k] * self.inv_fact[k - r] * self.inv_fact[r]) % self.MOD



    def combination2(self, k, r):

        """kCrを求める O(r) kが大きいが、r <= nを満たしているときに使用"""

        if k < r:

            return 0

        res = 1

        for l in range(r):

            res *= (k - l)

            res %= self.MOD

        return (res * self.inv_fact[r]) % self.MOD





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

MOD = 10 ** 9 + 7

comb = Combination(2 * 10 ** 5 + 10, MOD)



all_ptn =pow(2, n, MOD)

a_ptn = comb.combination2(n, a)

b_ptn = comb.combination2(n, b)



ans = (all_ptn - (a_ptn + b_ptn) - 1) % MOD

print(ans)
import sys

input = sys.stdin.buffer.readline





def combination(k, r, MOD):

    """kCrを求める"""

    if k < r:

        return 0

    r = min(r, k - r)

    numer, denom = 1, 1

    for l in range(r):

        numer *= (k - l)

        numer %= MOD

        denom *= l + 1

        denom %= MOD

    return numer * pow(denom, MOD - 2, MOD) % MOD





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

MOD = 10 ** 9 + 7





all_ptn = pow(2, n, MOD)

a_ptn = combination(n, a, MOD)

b_ptn = combination(n, b, MOD)



ans = (all_ptn - (a_ptn + b_ptn) - 1) % MOD

print(ans)
class Combination:
    """階乗とその逆元のテーブルをO(N)で事前作成し、組み合わせの計算をO(1)で行う"""

    def __init__(self, n, MOD):
        self.fact = [1]
        for i in range(1, n + 1):
            self.fact.append(self.fact[-1] * i % MOD)
        self.inv_fact = [0] * (n + 1)
        self.inv_fact[n] = pow(self.fact[n], MOD - 2, MOD)
        for i in reversed(list(range(n))):
            self.inv_fact[i] = self.inv_fact[i + 1] * (i + 1) % MOD
        self.MOD = MOD

    def factorial(self, k):
        """k!を求める O(1)"""
        return self.fact[k]

    def inverse_factorial(self, k):
        """k!の逆元を求める O(1)"""
        return self.inv_fact[k]

    def permutation(self, k, r):
        """kPrを求める O(1)"""
        if k < r:
            return 0
        return (self.fact[k] * self.inv_fact[k - r]) % self.MOD

    def combination(self, k, r):
        """kCrを求める O(1)"""
        if k < r:
            return 0
        return (self.fact[k] * self.inv_fact[k - r] * self.inv_fact[r]) % self.MOD

    def combination2(self, k, r):
        """kCrを求める O(r) kが大きいが、r <= nを満たしているときに使用"""
        if k < r:
            return 0
        res = 1
        for l in range(r):
            res *= k - l
            res %= self.MOD
        return (res * self.inv_fact[r]) % self.MOD


n, a, b = list(map(int, input().split()))
MOD = 10**9 + 7
comb = Combination(2 * 10**5 + 10, MOD)
all_ptn = pow(2, n, MOD)
a_ptn = comb.combination2(n, a)
b_ptn = comb.combination2(n, b)
ans = (all_ptn - (a_ptn + b_ptn) - 1) % MOD
print(ans)

import sys

input = sys.stdin.buffer.readline


def combination(k, r, MOD):
    """kCrを求める"""
    if k < r:
        return 0
    r = min(r, k - r)
    numer, denom = 1, 1
    for l in range(r):
        numer *= k - l
        numer %= MOD
        denom *= l + 1
        denom %= MOD
    return numer * pow(denom, MOD - 2, MOD) % MOD


n, a, b = list(map(int, input().split()))
MOD = 10**9 + 7
all_ptn = pow(2, n, MOD)
a_ptn = combination(n, a, MOD)
b_ptn = combination(n, b, MOD)
ans = (all_ptn - (a_ptn + b_ptn) - 1) % MOD
print(ans)

-class Combination: -    """階乗とその逆元のテーブルをO(N)で事前作成し、組み合わせの計算をO(1)で行う""" +import sys -    def __init__(self, n, MOD): -        self.fact = [1] -        for i in range(1, n + 1): -            self.fact.append(self.fact[-1] * i % MOD) -        self.inv_fact = [0] * (n + 1) -        self.inv_fact[n] = pow(self.fact[n], MOD - 2, MOD) -        for i in reversed(list(range(n))): -            self.inv_fact[i] = self.inv_fact[i + 1] * (i + 1) % MOD -        self.MOD = MOD +input = sys.stdin.buffer.readline -    def factorial(self, k): -        """k!を求める O(1)""" -        return self.fact[k] -    def inverse_factorial(self, k): -        """k!の逆元を求める O(1)""" -        return self.inv_fact[k] - -    def permutation(self, k, r): -        """kPrを求める O(1)""" -        if k < r: -            return 0 -        return (self.fact[k] * self.inv_fact[k - r]) % self.MOD - -    def combination(self, k, r): -        """kCrを求める O(1)""" -        if k < r: -            return 0 -        return (self.fact[k] * self.inv_fact[k - r] * self.inv_fact[r]) % self.MOD - -    def combination2(self, k, r): -        """kCrを求める O(r) kが大きいが、r <= nを満たしているときに使用""" -        if k < r: -            return 0 -        res = 1 -        for l in range(r): -            res *= k - l -            res %= self.MOD -        return (res * self.inv_fact[r]) % self.MOD +def combination(k, r, MOD): +    """kCrを求める""" +    if k < r: +        return 0 +    r = min(r, k - r) +    numer, denom = 1, 1 +    for l in range(r): +        numer *= k - l +        numer %= MOD +        denom *= l + 1 +        denom %= MOD +    return numer * pow(denom, MOD - 2, MOD) % MOD -comb = Combination(2 * 10**5 + 10, MOD) -a_ptn = comb.combination2(n, a) -b_ptn = comb.combination2(n, b) +a_ptn = combination(n, a, MOD) +b_ptn = combination(n, b, MOD)