M=10**9+7

def comb(n,k):

  a=b=1

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

    a=a*n%M

    b=b*i%M

    n-=1

  return a*pow(b,M-2,M)

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

print(((pow(2,n,M)-1-comb(n,a)-comb(n,b))%M))
M=10**9+7

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

def f(k):

 a=b=1;m=n

 for i in range(k):a=a*m%M;b=b*-~i%M;m-=1

 return a*pow(b,M-2,M)

print(((~f(a)-f(b)+pow(2,n,M))%M))
M = 10**9 + 7


def comb(n, k):
    a = b = 1
    for i in range(1, k + 1):
        a = a * n % M
        b = b * i % M
        n -= 1
    return a * pow(b, M - 2, M)


n, a, b = list(map(int, input().split()))
print(((pow(2, n, M) - 1 - comb(n, a) - comb(n, b)) % M))

M = 10**9 + 7
n, a, b = list(map(int, input().split()))


def f(k):
    a = b = 1
    m = n
    for i in range(k):
        a = a * m % M
        b = b * -~i % M
        m -= 1
    return a * pow(b, M - 2, M)


print(((~f(a) - f(b) + pow(2, n, M)) % M))

+n, a, b = list(map(int, input().split())) -def comb(n, k): +def f(k): -    for i in range(1, k + 1): -        a = a * n % M -        b = b * i % M -        n -= 1 +    m = n +    for i in range(k): +        a = a * m % M +        b = b * -~i % M +        m -= 1 -n, a, b = list(map(int, input().split())) -print(((pow(2, n, M) - 1 - comb(n, a) - comb(n, b)) % M)) +print(((~f(a) - f(b) + pow(2, n, M)) % M))