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

def C(n,r):
    p = n*pow(r,MOD-2,MOD)
    for i in range(1,r):
        p = p*(n-i)%MOD
        p = p * pow(i,MOD-2,MOD)
    return p%MOD



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

def C(n,r):
    p = n*pow(r,MOD-2,MOD)
    for i in range(1,r):
        p = p*(n-i)%MOD
        p = p * pow(i,MOD-2,MOD)
    return p%MOD



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