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

nCa=1
nCb=1

tmp=n
for i in range(a):
    nCa*=tmp
    tmp-=1
    nCa%=mod
nCa=nCa*pow(factorial(a),mod-2,mod)%mod
tmp=n
for i in range(b):
    nCb*=tmp
    tmp-=1
    nCb%=mod
nCb=nCb*pow(factorial(b),mod-2,mod)%mod

print(((pow(2,n,mod))-nCa-nCb-1)%mod) from math import factorial 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 nCa=1 nCa 1 nCb=1 nCb 1 tmp=n tmp n for i in range(a):
    nCa*=tmp
    tmp-=1
    nCa%=mod i range(a) range a nCa*=tmp nCa tmp tmp-=1 tmp 1 nCa%=mod nCa mod nCa=nCa*pow(factorial(a),mod-2,mod)%mod nCa nCa*pow(factorial(a),mod-2,mod)%mod nCa*pow(factorial(a),mod-2,mod) nCa pow(factorial(a),mod-2,mod) pow factorial(a) factorial a mod-2 mod 2 mod mod tmp=n tmp n for i in range(b):
    nCb*=tmp
    tmp-=1
    nCb%=mod i range(b) range b nCb*=tmp nCb tmp tmp-=1 tmp 1 nCb%=mod nCb mod nCb=nCb*pow(factorial(b),mod-2,mod)%mod nCb nCb*pow(factorial(b),mod-2,mod)%mod nCb*pow(factorial(b),mod-2,mod) nCb pow(factorial(b),mod-2,mod) pow factorial(b) factorial b mod-2 mod 2 mod mod print(((pow(2,n,mod))-nCa-nCb-1)%mod) print ((pow(2,n,mod))-nCa-nCb-1)%mod (pow(2,n,mod))-nCa-nCb-1 (pow(2,n,mod))-nCa-nCb (pow(2,n,mod))-nCa pow(2,n,mod) pow 2 n mod nCa nCb 1 mod b=map(int,input().split()) map(int,input().split()) b nCb%=mod mod nCb nCa%=mod mod nCa a,b=map(int,input().split()) map(int,input().split()) a tmp=n n tmp nCa=1 1 nCa nCa=nCa*pow(factorial(a),mod-2,mod)%mod nCa*pow(factorial(a),mod-2,mod)%mod nCa tmp=n n tmp mod=10**9+7 10**9+7 mod nCa*=tmp tmp nCa n,a,b=map(int,input().split()) map(int,input().split()) n nCb=nCb*pow(factorial(b),mod-2,mod)%mod nCb*pow(factorial(b),mod-2,mod)%mod nCb tmp-=1 1 tmp nCb=1 1 nCb nCb*=tmp tmp nCb tmp-=1 1 tmp
from math import factorial
n,a,b=map(int,input().split())
mod=10**9+7

nCa=1
nCb=1

tmp=n
for i in range(a):
    nCa*=tmp
    tmp-=1
    nCa%=mod
nCa=nCa*pow(factorial(a),mod-2,mod)%mod
tmp=n
for i in range(b):
    nCb*=tmp
    tmp-=1
    nCb%=mod
nCb=nCb*pow(factorial(b),mod-2,mod)%mod

print(((pow(2,n,mod))-nCa-nCb-1)%mod)