n,a,b = map(int,input().split())
#組み合わせ(数が大きいとき)(10**9+7で割ったもの)
q = 10**9+7
def comb(a, b):
    c = 1
    for i in range(b):
        c *= a - i
        c %= q
    d = 1
    for i in range(b):
        d *= i + 1
        d %= q
    return c*pow(d, q-2, q)
p = pow(2,n,q)-1-comb(n,a)-comb(n,b)
print(p%(10**9+7)) n,a,b = map(int,input().split()) n map(int,input().split()) map int input().split() ().split () input split a b q = 10**9+7 q 10**9+7 10**9 10 9 7 def comb(a, b):
    c = 1
    for i in range(b):
        c *= a - i
        c %= q
    d = 1
    for i in range(b):
        d *= i + 1
        d %= q
    return c*pow(d, q-2, q) comb c = 1 c 1 for i in range(b):
        c *= a - i
        c %= q
     i range(b) range b c *= a - i c a - i a i c %= q c q d = 1 d 1 for i in range(b):
        d *= i + 1
        d %= q
     i range(b) range b d *= i + 1 d i + 1 i 1 d %= q d q return c*pow(d, q-2, q) c*pow(d, q-2, q) c pow(d, q-2, q) pow d q-2 q 2 q a a b b p = pow(2,n,q)-1-comb(n,a)-comb(n,b) p pow(2,n,q)-1-comb(n,a)-comb(n,b) pow(2,n,q)-1-comb(n,a) pow(2,n,q)-1 pow(2,n,q) pow 2 n q 1 comb(n,a) comb n a comb(n,b) comb n b print(p%(10**9+7)) print p%(10**9+7) p 10**9+7 10**9 10 9 7 n,a,b = map(int,input().split()) map(int,input().split()) n a,b = map(int,input().split()) map(int,input().split()) a b = map(int,input().split()) map(int,input().split()) b q = 10**9+7 10**9+7 q def comb(a, b):
    c = 1
    for i in range(b):
        c *= a - i
        c %= q
    d = 1
    for i in range(b):
        d *= i + 1
        d %= q
    return c*pow(d, q-2, q) def comb(a, b):
    c = 1
    for i in range(b):
        c *= a - i
        c %= q
    d = 1
    for i in range(b):
        d *= i + 1
        d %= q
    return c*pow(d, q-2, q) comb p = pow(2,n,q)-1-comb(n,a)-comb(n,b) pow(2,n,q)-1-comb(n,a)-comb(n,b) p
n,a,b = map(int,input().split())
#組み合わせ(数が大きいとき)(10**9+7で割ったもの)
q = 10**9+7
def comb(a, b):
    c = 1
    for i in range(b):
        c *= a - i
        c %= q
    d = 1
    for i in range(b):
        d *= i + 1
        d %= q
    return c*pow(d, q-2, q)
p = pow(2,n,q)-1-comb(n,a)-comb(n,b)
print(p%(10**9+7))