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

def comb(n, k):
    nCk = 1


    for i in range(n - k + 1, n + 1):
        nCk *= i
        nCk %= MOD

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

print((((pow(2,n,MOD)-1-comb(n,a))%MOD)-comb(n,b))%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 comb(n, k):
    nCk = 1


    for i in range(n - k + 1, n + 1):
        nCk *= i
        nCk %= MOD

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

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


    for i in range(n - k + 1, n + 1):
        nCk *= i
        nCk %= MOD

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


    for i in range(n - k + 1, n + 1):
        nCk *= i
        nCk %= MOD

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

def comb(n, k):
    nCk = 1


    for i in range(n - k + 1, n + 1):
        nCk *= i
        nCk %= MOD

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

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