n,a,b=map(int,input().split())
def fact(n,p):
    a=1
    for i in range(1,n+1):
        a=(a*i)%p
    return a
def bfact(n,x,p):
    a=1
    for i in range(n-x+1,n+1):
        a=(a*i)%p
    return a
p=10**9+7
na=bfact(n,a,p)%p
nb=bfact(n,b,p)%p
aa=fact(a,p)%p
bb=fact(b,p)%p
aaa=pow(aa,-1,p)
bbb=pow(bb,-1,p)
ans=pow(2,n,p)-1
ans-=(na*aaa+nb*bbb)
print(ans%p) n,a,b=map(int,input().split()) n map(int,input().split()) map int input().split() ().split () input split a b def fact(n,p):
    a=1
    for i in range(1,n+1):
        a=(a*i)%p
    return a fact a=1 a 1 for i in range(1,n+1):
        a=(a*i)%p
     i range(1,n+1) range 1 n+1 n 1 a=(a*i)%p a (a*i)%p a*i a i p return a a n n p p def bfact(n,x,p):
    a=1
    for i in range(n-x+1,n+1):
        a=(a*i)%p
    return a bfact a=1 a 1 for i in range(n-x+1,n+1):
        a=(a*i)%p
     i range(n-x+1,n+1) range n-x+1 n-x n x 1 n+1 n 1 a=(a*i)%p a (a*i)%p a*i a i p return a a n n x x p p p=10**9+7 p 10**9+7 10**9 10 9 7 na=bfact(n,a,p)%p na bfact(n,a,p)%p bfact(n,a,p) bfact n a p p nb=bfact(n,b,p)%p nb bfact(n,b,p)%p bfact(n,b,p) bfact n b p p aa=fact(a,p)%p aa fact(a,p)%p fact(a,p) fact a p p bb=fact(b,p)%p bb fact(b,p)%p fact(b,p) fact b p p aaa=pow(aa,-1,p) aaa pow(aa,-1,p) pow aa -1 p bbb=pow(bb,-1,p) bbb pow(bb,-1,p) pow bb -1 p ans=pow(2,n,p)-1 ans pow(2,n,p)-1 pow(2,n,p) pow 2 n p 1 ans-=(na*aaa+nb*bbb) ans na*aaa+nb*bbb na*aaa na aaa nb*bbb nb bbb print(ans%p) print ans%p ans p na=bfact(n,a,p)%p bfact(n,a,p)%p na aa=fact(a,p)%p fact(a,p)%p aa bb=fact(b,p)%p fact(b,p)%p bb def bfact(n,x,p):
    a=1
    for i in range(n-x+1,n+1):
        a=(a*i)%p
    return a def bfact(n,x,p):
    a=1
    for i in range(n-x+1,n+1):
        a=(a*i)%p
    return a bfact b=map(int,input().split()) map(int,input().split()) b p=10**9+7 10**9+7 p nb=bfact(n,b,p)%p bfact(n,b,p)%p nb aaa=pow(aa,-1,p) pow(aa,-1,p) aaa ans-=(na*aaa+nb*bbb) na*aaa+nb*bbb ans def fact(n,p):
    a=1
    for i in range(1,n+1):
        a=(a*i)%p
    return a def fact(n,p):
    a=1
    for i in range(1,n+1):
        a=(a*i)%p
    return a fact a,b=map(int,input().split()) map(int,input().split()) a ans=pow(2,n,p)-1 pow(2,n,p)-1 ans bbb=pow(bb,-1,p) pow(bb,-1,p) bbb n,a,b=map(int,input().split()) map(int,input().split()) n
n,a,b=map(int,input().split())
def fact(n,p):
    a=1
    for i in range(1,n+1):
        a=(a*i)%p
    return a
def bfact(n,x,p):
    a=1
    for i in range(n-x+1,n+1):
        a=(a*i)%p
    return a
p=10**9+7
na=bfact(n,a,p)%p
nb=bfact(n,b,p)%p
aa=fact(a,p)%p
bb=fact(b,p)%p
aaa=pow(aa,-1,p)
bbb=pow(bb,-1,p)
ans=pow(2,n,p)-1
ans-=(na*aaa+nb*bbb)
print(ans%p)