n, a, b = map(int,input().split())

mod = 10**9+7

def combi(n,r):
    x, y = 1,1
    for i in range(n-r+1,n+1):
        x *= i
        x %= mod
        
    for j in range(1,r+1):
        y *= j
        y %= mod
    yinv = pow(y,mod-2,mod)
    
    return x*yinv%mod

def main():
    nca = combi(n,a)
    ncb = combi(n,b)
    ans = pow(2,n,mod)-1 - (nca + ncb)
        
    print(ans%mod)
    
main() 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 combi(n,r):
    x, y = 1,1
    for i in range(n-r+1,n+1):
        x *= i
        x %= mod
        
    for j in range(1,r+1):
        y *= j
        y %= mod
    yinv = pow(y,mod-2,mod)
    
    return x*yinv%mod combi x, y = 1,1 x 1 y 1 for i in range(n-r+1,n+1):
        x *= i
        x %= mod
        
     i range(n-r+1,n+1) range n-r+1 n-r n r 1 n+1 n 1 x *= i x i x %= mod x mod for j in range(1,r+1):
        y *= j
        y %= mod
     j range(1,r+1) range 1 r+1 r 1 y *= j y j y %= mod y mod yinv = pow(y,mod-2,mod) yinv pow(y,mod-2,mod) pow y mod-2 mod 2 mod return x*yinv%mod x*yinv%mod x*yinv x yinv mod n n r r def main():
    nca = combi(n,a)
    ncb = combi(n,b)
    ans = pow(2,n,mod)-1 - (nca + ncb)
        
    print(ans%mod)
     main nca = combi(n,a) nca combi(n,a) combi n a ncb = combi(n,b) ncb combi(n,b) combi n b ans = pow(2,n,mod)-1 - (nca + ncb) ans pow(2,n,mod)-1 - (nca + ncb) pow(2,n,mod)-1 pow(2,n,mod) pow 2 n mod 1 nca + ncb nca ncb print(ans%mod) print ans%mod ans mod main() main def combi(n,r):
    x, y = 1,1
    for i in range(n-r+1,n+1):
        x *= i
        x %= mod
        
    for j in range(1,r+1):
        y *= j
        y %= mod
    yinv = pow(y,mod-2,mod)
    
    return x*yinv%mod def combi(n,r):
    x, y = 1,1
    for i in range(n-r+1,n+1):
        x *= i
        x %= mod
        
    for j in range(1,r+1):
        y *= j
        y %= mod
    yinv = pow(y,mod-2,mod)
    
    return x*yinv%mod combi mod = 10**9+7 10**9+7 mod 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 def main():
    nca = combi(n,a)
    ncb = combi(n,b)
    ans = pow(2,n,mod)-1 - (nca + ncb)
        
    print(ans%mod)
     def main():
    nca = combi(n,a)
    ncb = combi(n,b)
    ans = pow(2,n,mod)-1 - (nca + ncb)
        
    print(ans%mod)
     main
n, a, b = map(int,input().split())

mod = 10**9+7

def combi(n,r):
    x, y = 1,1
    for i in range(n-r+1,n+1):
        x *= i
        x %= mod
        
    for j in range(1,r+1):
        y *= j
        y %= mod
    yinv = pow(y,mod-2,mod)
    
    return x*yinv%mod

def main():
    nca = combi(n,a)
    ncb = combi(n,b)
    ans = pow(2,n,mod)-1 - (nca + ncb)
        
    print(ans%mod)
    
main()