def cmb(n,k,p):
    x,y = 1,1
    for i in range(k):
        x = x * (n-i) % p
        y = y * (i+1) % p
    res = x * pow(y,p-2,p) % p
    return res

N,A,B = map(int,input().split())
mod = 10**9+7
print((pow(2,N,mod)-cmb(N,A,mod)-cmb(N,B,mod)-1)%mod) def cmb(n,k,p):
    x,y = 1,1
    for i in range(k):
        x = x * (n-i) % p
        y = y * (i+1) % p
    res = x * pow(y,p-2,p) % p
    return res cmb x,y = 1,1 x 1 y 1 for i in range(k):
        x = x * (n-i) % p
        y = y * (i+1) % p
     i range(k) range k x = x * (n-i) % p x x * (n-i) % p x * (n-i) x n-i n i p y = y * (i+1) % p y y * (i+1) % p y * (i+1) y i+1 i 1 p res = x * pow(y,p-2,p) % p res x * pow(y,p-2,p) % p x * pow(y,p-2,p) x pow(y,p-2,p) pow y p-2 p 2 p p return res res n n k k p p 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 print((pow(2,N,mod)-cmb(N,A,mod)-cmb(N,B,mod)-1)%mod) print (pow(2,N,mod)-cmb(N,A,mod)-cmb(N,B,mod)-1)%mod pow(2,N,mod)-cmb(N,A,mod)-cmb(N,B,mod)-1 pow(2,N,mod)-cmb(N,A,mod)-cmb(N,B,mod) pow(2,N,mod)-cmb(N,A,mod) pow(2,N,mod) pow 2 N mod cmb(N,A,mod) cmb N A mod cmb(N,B,mod) cmb N B mod 1 mod A,B = map(int,input().split()) map(int,input().split()) A def cmb(n,k,p):
    x,y = 1,1
    for i in range(k):
        x = x * (n-i) % p
        y = y * (i+1) % p
    res = x * pow(y,p-2,p) % p
    return res def cmb(n,k,p):
    x,y = 1,1
    for i in range(k):
        x = x * (n-i) % p
        y = y * (i+1) % p
    res = x * pow(y,p-2,p) % p
    return res cmb N,A,B = map(int,input().split()) map(int,input().split()) N B = map(int,input().split()) map(int,input().split()) B mod = 10**9+7 10**9+7 mod
def cmb(n,k,p):
    x,y = 1,1
    for i in range(k):
        x = x * (n-i) % p
        y = y * (i+1) % p
    res = x * pow(y,p-2,p) % p
    return res

N,A,B = map(int,input().split())
mod = 10**9+7
print((pow(2,N,mod)-cmb(N,A,mod)-cmb(N,B,mod)-1)%mod)