n, a, b = map(int, input().split())
mod = pow(10, 9) + 7
total = pow(2, n, mod)
#print(total)
def comb(m, x):
  numerator = 1
  for i in range(m - x + 1, m + 1):
    numerator = numerator * i % mod
  denominator = 1
  for i in range(1, x + 1):
    denominator = denominator * i % mod
  d = pow(denominator, mod - 2, mod)
  return numerator * d
a = comb(n, a)
b = comb(n, b)
print((total - a - b - 1) % mod) n, a, b = map(int, input().split()) n map(int, input().split()) map int input().split() ().split () input split a b mod = pow(10, 9) + 7 mod pow(10, 9) + 7 pow(10, 9) pow 10 9 7 total = pow(2, n, mod) total pow(2, n, mod) pow 2 n mod def comb(m, x):
  numerator = 1
  for i in range(m - x + 1, m + 1):
    numerator = numerator * i % mod
  denominator = 1
  for i in range(1, x + 1):
    denominator = denominator * i % mod
  d = pow(denominator, mod - 2, mod)
  return numerator * d comb numerator = 1 numerator 1 for i in range(m - x + 1, m + 1):
    numerator = numerator * i % mod
   i range(m - x + 1, m + 1) range m - x + 1 m - x m x 1 m + 1 m 1 numerator = numerator * i % mod numerator numerator * i % mod numerator * i numerator i mod denominator = 1 denominator 1 for i in range(1, x + 1):
    denominator = denominator * i % mod
   i range(1, x + 1) range 1 x + 1 x 1 denominator = denominator * i % mod denominator denominator * i % mod denominator * i denominator i mod d = pow(denominator, mod - 2, mod) d pow(denominator, mod - 2, mod) pow denominator mod - 2 mod 2 mod return numerator * d numerator * d numerator d m m x x a = comb(n, a) a comb(n, a) comb n a b = comb(n, b) b comb(n, b) comb n b print((total - a - b - 1) % mod) print (total - a - b - 1) % mod total - a - b - 1 total - a - b total - a total a b 1 mod b = comb(n, b) comb(n, b) b a, b = map(int, input().split()) map(int, input().split()) a b = map(int, input().split()) map(int, input().split()) b total = pow(2, n, mod) pow(2, n, mod) total def comb(m, x):
  numerator = 1
  for i in range(m - x + 1, m + 1):
    numerator = numerator * i % mod
  denominator = 1
  for i in range(1, x + 1):
    denominator = denominator * i % mod
  d = pow(denominator, mod - 2, mod)
  return numerator * d def comb(m, x):
  numerator = 1
  for i in range(m - x + 1, m + 1):
    numerator = numerator * i % mod
  denominator = 1
  for i in range(1, x + 1):
    denominator = denominator * i % mod
  d = pow(denominator, mod - 2, mod)
  return numerator * d comb a = comb(n, a) comb(n, a) a mod = pow(10, 9) + 7 pow(10, 9) + 7 mod n, a, b = map(int, input().split()) map(int, input().split()) n
n, a, b = map(int, input().split())
mod = pow(10, 9) + 7
total = pow(2, n, mod)
#print(total)
def comb(m, x):
  numerator = 1
  for i in range(m - x + 1, m + 1):
    numerator = numerator * i % mod
  denominator = 1
  for i in range(1, x + 1):
    denominator = denominator * i % mod
  d = pow(denominator, mod - 2, mod)
  return numerator * d
a = comb(n, a)
b = comb(n, b)
print((total - a - b - 1) % mod)