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

def power_func(a,n,mod):
  bi=str(format(n,"b"))
  res=1
  for i in range(len(bi)):
    res=(res*res)%mod
    if bi[i]=='1':
      res=(res*a)%mod
  return res

def cmb1(x,y,mod):
  l=1
  for g in  range(x+1-y,x+1):
    l*=g
    l%=mod
  for k in range(1,y+1):
    l*=power_func(k,mod-2,mod)
    l%=mod
    
  return l
    
  return ans

ans=power_func(2,n,mod)-1
ans1=cmb1(n,a,mod)
ans2=cmb1(n,b,mod)

print((ans-ans1-ans2)%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 power_func(a,n,mod):
  bi=str(format(n,"b"))
  res=1
  for i in range(len(bi)):
    res=(res*res)%mod
    if bi[i]=='1':
      res=(res*a)%mod
  return res power_func bi=str(format(n,"b")) bi str(format(n,"b")) str format(n,"b") format n "b" res=1 res 1 for i in range(len(bi)):
    res=(res*res)%mod
    if bi[i]=='1':
      res=(res*a)%mod
   i range(len(bi)) range len(bi) len bi res=(res*res)%mod res (res*res)%mod res*res res res mod if bi[i]=='1':
      res=(res*a)%mod
   bi[i]=='1' bi[i] bi i '1' res=(res*a)%mod res (res*a)%mod res*a res a mod return res res a a n n mod mod def cmb1(x,y,mod):
  l=1
  for g in  range(x+1-y,x+1):
    l*=g
    l%=mod
  for k in range(1,y+1):
    l*=power_func(k,mod-2,mod)
    l%=mod
    
  return l
    
  return ans cmb1 l=1 l 1 for g in  range(x+1-y,x+1):
    l*=g
    l%=mod
   g range(x+1-y,x+1) range x+1-y x+1 x 1 y x+1 x 1 l*=g l g l%=mod l mod for k in range(1,y+1):
    l*=power_func(k,mod-2,mod)
    l%=mod
    
   k range(1,y+1) range 1 y+1 y 1 l*=power_func(k,mod-2,mod) l power_func(k,mod-2,mod) power_func k mod-2 mod 2 mod l%=mod l mod return l l return ans ans x x y y mod mod ans=power_func(2,n,mod)-1 ans power_func(2,n,mod)-1 power_func(2,n,mod) power_func 2 n mod 1 ans1=cmb1(n,a,mod) ans1 cmb1(n,a,mod) cmb1 n a mod ans2=cmb1(n,b,mod) ans2 cmb1(n,b,mod) cmb1 n b mod print((ans-ans1-ans2)%mod) print (ans-ans1-ans2)%mod ans-ans1-ans2 ans-ans1 ans ans1 ans2 mod b=map(int,input().split()) map(int,input().split()) b mod=10**9+7 10**9+7 mod ans1=cmb1(n,a,mod) cmb1(n,a,mod) ans1 def power_func(a,n,mod):
  bi=str(format(n,"b"))
  res=1
  for i in range(len(bi)):
    res=(res*res)%mod
    if bi[i]=='1':
      res=(res*a)%mod
  return res def power_func(a,n,mod):
  bi=str(format(n,"b"))
  res=1
  for i in range(len(bi)):
    res=(res*res)%mod
    if bi[i]=='1':
      res=(res*a)%mod
  return res power_func def cmb1(x,y,mod):
  l=1
  for g in  range(x+1-y,x+1):
    l*=g
    l%=mod
  for k in range(1,y+1):
    l*=power_func(k,mod-2,mod)
    l%=mod
    
  return l
    
  return ans def cmb1(x,y,mod):
  l=1
  for g in  range(x+1-y,x+1):
    l*=g
    l%=mod
  for k in range(1,y+1):
    l*=power_func(k,mod-2,mod)
    l%=mod
    
  return l
    
  return ans cmb1 ans=power_func(2,n,mod)-1 power_func(2,n,mod)-1 ans ans2=cmb1(n,b,mod) cmb1(n,b,mod) ans2 a,b=map(int,input().split()) map(int,input().split()) a n,a,b=map(int,input().split()) map(int,input().split()) n
n,a,b=map(int,input().split())
mod=10**9+7

def power_func(a,n,mod):
  bi=str(format(n,"b"))
  res=1
  for i in range(len(bi)):
    res=(res*res)%mod
    if bi[i]=='1':
      res=(res*a)%mod
  return res

def cmb1(x,y,mod):
  l=1
  for g in  range(x+1-y,x+1):
    l*=g
    l%=mod
  for k in range(1,y+1):
    l*=power_func(k,mod-2,mod)
    l%=mod
    
  return l
    
  return ans

ans=power_func(2,n,mod)-1
ans1=cmb1(n,a,mod)
ans2=cmb1(n,b,mod)

print((ans-ans1-ans2)%mod)