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

MOD = 10 ** 9 + 7

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

ans = pow(2, n, MOD) - 1
ans -= nCk(n, a)
ans -= nCk(n, b)
print(ans % MOD) 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 nCk(n, k):
    num = 1
    for i in range(n, n - k, -1):
        num *= i
        num %= MOD
    tmp = 1
    for i in range(1, k + 1):
        tmp *= i
        tmp %= MOD
    num *= pow(tmp, MOD - 2, MOD)
    return num nCk num = 1 num 1 for i in range(n, n - k, -1):
        num *= i
        num %= MOD
     i range(n, n - k, -1) range n n - k n k -1 num *= i num i num %= MOD num MOD tmp = 1 tmp 1 for i in range(1, k + 1):
        tmp *= i
        tmp %= MOD
     i range(1, k + 1) range 1 k + 1 k 1 tmp *= i tmp i tmp %= MOD tmp MOD num *= pow(tmp, MOD - 2, MOD) num pow(tmp, MOD - 2, MOD) pow tmp MOD - 2 MOD 2 MOD return num num n n k k ans = pow(2, n, MOD) - 1 ans pow(2, n, MOD) - 1 pow(2, n, MOD) pow 2 n MOD 1 ans -= nCk(n, a) ans nCk(n, a) nCk n a ans -= nCk(n, b) ans nCk(n, b) nCk n b print(ans % MOD) print ans % MOD ans MOD a, b = map(int, input().split()) map(int, input().split()) a ans = pow(2, n, MOD) - 1 pow(2, n, MOD) - 1 ans b = map(int, input().split()) map(int, input().split()) b MOD = 10 ** 9 + 7 10 ** 9 + 7 MOD ans -= nCk(n, a) nCk(n, a) ans n, a, b = map(int, input().split()) map(int, input().split()) n def nCk(n, k):
    num = 1
    for i in range(n, n - k, -1):
        num *= i
        num %= MOD
    tmp = 1
    for i in range(1, k + 1):
        tmp *= i
        tmp %= MOD
    num *= pow(tmp, MOD - 2, MOD)
    return num def nCk(n, k):
    num = 1
    for i in range(n, n - k, -1):
        num *= i
        num %= MOD
    tmp = 1
    for i in range(1, k + 1):
        tmp *= i
        tmp %= MOD
    num *= pow(tmp, MOD - 2, MOD)
    return num nCk ans -= nCk(n, b) nCk(n, b) ans
n, a, b = map(int, input().split())

MOD = 10 ** 9 + 7

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

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