from math import factorial
n, a, b = [int(i) for i in input().split()]
mod = 10 ** 9 + 7

def nCr(n, r):
    global mod
    ans = 1
    for i in range(r):
        ans = (ans * (n-i)) % mod
    return (ans * pow(factorial(r), mod-2, mod)) % mod

print((pow(2, n, mod) - nCr(n, a) - nCr(n, b) - 1) % mod)  from math import factorial int(i) for i in input().split() for i in input().split() i input().split() ().split () input split for i in input().split() int(i) int i n, a, b = [int(i) for i in input().split()] n [int(i) for i in input().split()] a b mod = 10 ** 9 + 7 mod 10 ** 9 + 7 10 ** 9 10 9 7 def nCr(n, r):
    global mod
    ans = 1
    for i in range(r):
        ans = (ans * (n-i)) % mod
    return (ans * pow(factorial(r), mod-2, mod)) % mod nCr global mod ans = 1 ans 1 for i in range(r):
        ans = (ans * (n-i)) % mod
     i range(r) range r ans = (ans * (n-i)) % mod ans (ans * (n-i)) % mod ans * (n-i) ans n-i n i mod return (ans * pow(factorial(r), mod-2, mod)) % mod (ans * pow(factorial(r), mod-2, mod)) % mod ans * pow(factorial(r), mod-2, mod) ans pow(factorial(r), mod-2, mod) pow factorial(r) factorial r mod-2 mod 2 mod mod n n r r print((pow(2, n, mod) - nCr(n, a) - nCr(n, b) - 1) % mod) print (pow(2, n, mod) - nCr(n, a) - nCr(n, b) - 1) % mod pow(2, n, mod) - nCr(n, a) - nCr(n, b) - 1 pow(2, n, mod) - nCr(n, a) - nCr(n, b) pow(2, n, mod) - nCr(n, a) pow(2, n, mod) pow 2 n mod nCr(n, a) nCr n a nCr(n, b) nCr n b 1 mod def nCr(n, r):
    global mod
    ans = 1
    for i in range(r):
        ans = (ans * (n-i)) % mod
    return (ans * pow(factorial(r), mod-2, mod)) % mod def nCr(n, r):
    global mod
    ans = 1
    for i in range(r):
        ans = (ans * (n-i)) % mod
    return (ans * pow(factorial(r), mod-2, mod)) % mod nCr a, b = [int(i) for i in input().split()] [int(i) for i in input().split()] a mod = 10 ** 9 + 7 10 ** 9 + 7 mod b = [int(i) for i in input().split()] [int(i) for i in input().split()] b n, a, b = [int(i) for i in input().split()] [int(i) for i in input().split()] n
from math import factorial
n, a, b = [int(i) for i in input().split()]
mod = 10 ** 9 + 7

def nCr(n, r):
    global mod
    ans = 1
    for i in range(r):
        ans = (ans * (n-i)) % mod
    return (ans * pow(factorial(r), mod-2, mod)) % mod

print((pow(2, n, mod) - nCr(n, a) - nCr(n, b) - 1) % mod) 