from functools import reduce

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

mod=10**9+7
def nCk(n,k):
    if n<k or (n<0 or k<0):
        return 0
    k=min(k,n-k)
    up,down=1,1
    for i in range(k):
        up=up*(n-i)%mod
        down=down*(i+1)%mod
    return up*pow(down,mod-2,mod)%mod

all=pow(2,n,mod)
nCa=nCk(n,a)
nCb=nCk(n,b)

print((all-nCa-nCb-1)%mod) from functools import reduce 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 nCk(n,k):
    if n<k or (n<0 or k<0):
        return 0
    k=min(k,n-k)
    up,down=1,1
    for i in range(k):
        up=up*(n-i)%mod
        down=down*(i+1)%mod
    return up*pow(down,mod-2,mod)%mod nCk if n<k or (n<0 or k<0):
        return 0
     n<k or (n<0 or k<0) n<k n k n<0 or k<0 n<0 n 0 k<0 k 0 return 0 0 k=min(k,n-k) k min(k,n-k) min k n-k n k up,down=1,1 up 1 down 1 for i in range(k):
        up=up*(n-i)%mod
        down=down*(i+1)%mod
     i range(k) range k up=up*(n-i)%mod up up*(n-i)%mod up*(n-i) up n-i n i mod down=down*(i+1)%mod down down*(i+1)%mod down*(i+1) down i+1 i 1 mod return up*pow(down,mod-2,mod)%mod up*pow(down,mod-2,mod)%mod up*pow(down,mod-2,mod) up pow(down,mod-2,mod) pow down mod-2 mod 2 mod mod n n k k all=pow(2,n,mod) all pow(2,n,mod) pow 2 n mod nCa=nCk(n,a) nCa nCk(n,a) nCk n a nCb=nCk(n,b) nCb nCk(n,b) nCk n b print((all-nCa-nCb-1)%mod) print (all-nCa-nCb-1)%mod all-nCa-nCb-1 all-nCa-nCb all-nCa all nCa nCb 1 mod nCb=nCk(n,b) nCk(n,b) nCb a,b=map(int,input().split()) map(int,input().split()) a all=pow(2,n,mod) pow(2,n,mod) all nCa=nCk(n,a) nCk(n,a) nCa def nCk(n,k):
    if n<k or (n<0 or k<0):
        return 0
    k=min(k,n-k)
    up,down=1,1
    for i in range(k):
        up=up*(n-i)%mod
        down=down*(i+1)%mod
    return up*pow(down,mod-2,mod)%mod def nCk(n,k):
    if n<k or (n<0 or k<0):
        return 0
    k=min(k,n-k)
    up,down=1,1
    for i in range(k):
        up=up*(n-i)%mod
        down=down*(i+1)%mod
    return up*pow(down,mod-2,mod)%mod nCk n,a,b=map(int,input().split()) map(int,input().split()) n mod=10**9+7 10**9+7 mod b=map(int,input().split()) map(int,input().split()) b
from functools import reduce

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

mod=10**9+7
def nCk(n,k):
    if n<k or (n<0 or k<0):
        return 0
    k=min(k,n-k)
    up,down=1,1
    for i in range(k):
        up=up*(n-i)%mod
        down=down*(i+1)%mod
    return up*pow(down,mod-2,mod)%mod

all=pow(2,n,mod)
nCa=nCk(n,a)
nCb=nCk(n,b)

print((all-nCa-nCb-1)%mod)