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

def ruizyou(x,r,mod):
    sisuu=r
    kotae=1
    kake=x
    while sisuu:
        if sisuu&1==True:
            kotae*=kake
        sisuu>>=1
        kake**=2
        kake%=mod
        kotae%=mod
    return kotae

def conbi(n,r,mod):
    ue=1
    for i in range(n-r+1,n+1):
        ue*=i
        ue%=mod

    sita=1

    for i in range(1,r+1):
        sita*=i
        sita%=mod

    sita=ruizyou(sita,mod-2,mod)

    return (ue*sita)%mod

mod=10**9+7

ans=ruizyou(2,n,mod)-conbi(n,a,mod)-conbi(n,b,mod)-1
ans%=mod
print(ans) n,a,b = map(int, input().split()) n map(int, input().split()) map int input().split() ().split () input split a b def ruizyou(x,r,mod):
    sisuu=r
    kotae=1
    kake=x
    while sisuu:
        if sisuu&1==True:
            kotae*=kake
        sisuu>>=1
        kake**=2
        kake%=mod
        kotae%=mod
    return kotae ruizyou sisuu=r sisuu r kotae=1 kotae 1 kake=x kake x while sisuu:
        if sisuu&1==True:
            kotae*=kake
        sisuu>>=1
        kake**=2
        kake%=mod
        kotae%=mod
     sisuu if sisuu&1==True:
            kotae*=kake
         sisuu&1==True sisuu&1 sisuu 1 True kotae*=kake kotae kake sisuu>>=1 sisuu 1 kake**=2 kake 2 kake%=mod kake mod kotae%=mod kotae mod return kotae kotae x x r r mod mod def conbi(n,r,mod):
    ue=1
    for i in range(n-r+1,n+1):
        ue*=i
        ue%=mod

    sita=1

    for i in range(1,r+1):
        sita*=i
        sita%=mod

    sita=ruizyou(sita,mod-2,mod)

    return (ue*sita)%mod conbi ue=1 ue 1 for i in range(n-r+1,n+1):
        ue*=i
        ue%=mod

     i range(n-r+1,n+1) range n-r+1 n-r n r 1 n+1 n 1 ue*=i ue i ue%=mod ue mod sita=1 sita 1 for i in range(1,r+1):
        sita*=i
        sita%=mod

     i range(1,r+1) range 1 r+1 r 1 sita*=i sita i sita%=mod sita mod sita=ruizyou(sita,mod-2,mod) sita ruizyou(sita,mod-2,mod) ruizyou sita mod-2 mod 2 mod return (ue*sita)%mod (ue*sita)%mod ue*sita ue sita mod n n r r mod mod mod=10**9+7 mod 10**9+7 10**9 10 9 7 ans=ruizyou(2,n,mod)-conbi(n,a,mod)-conbi(n,b,mod)-1 ans ruizyou(2,n,mod)-conbi(n,a,mod)-conbi(n,b,mod)-1 ruizyou(2,n,mod)-conbi(n,a,mod)-conbi(n,b,mod) ruizyou(2,n,mod)-conbi(n,a,mod) ruizyou(2,n,mod) ruizyou 2 n mod conbi(n,a,mod) conbi n a mod conbi(n,b,mod) conbi n b mod 1 ans%=mod ans mod print(ans) print ans n,a,b = map(int, input().split()) map(int, input().split()) n b = map(int, input().split()) map(int, input().split()) b def ruizyou(x,r,mod):
    sisuu=r
    kotae=1
    kake=x
    while sisuu:
        if sisuu&1==True:
            kotae*=kake
        sisuu>>=1
        kake**=2
        kake%=mod
        kotae%=mod
    return kotae def ruizyou(x,r,mod):
    sisuu=r
    kotae=1
    kake=x
    while sisuu:
        if sisuu&1==True:
            kotae*=kake
        sisuu>>=1
        kake**=2
        kake%=mod
        kotae%=mod
    return kotae ruizyou ans=ruizyou(2,n,mod)-conbi(n,a,mod)-conbi(n,b,mod)-1 ruizyou(2,n,mod)-conbi(n,a,mod)-conbi(n,b,mod)-1 ans a,b = map(int, input().split()) map(int, input().split()) a mod=10**9+7 10**9+7 mod ans%=mod mod ans def conbi(n,r,mod):
    ue=1
    for i in range(n-r+1,n+1):
        ue*=i
        ue%=mod

    sita=1

    for i in range(1,r+1):
        sita*=i
        sita%=mod

    sita=ruizyou(sita,mod-2,mod)

    return (ue*sita)%mod def conbi(n,r,mod):
    ue=1
    for i in range(n-r+1,n+1):
        ue*=i
        ue%=mod

    sita=1

    for i in range(1,r+1):
        sita*=i
        sita%=mod

    sita=ruizyou(sita,mod-2,mod)

    return (ue*sita)%mod conbi
n,a,b = map(int, input().split())

def ruizyou(x,r,mod):
    sisuu=r
    kotae=1
    kake=x
    while sisuu:
        if sisuu&1==True:
            kotae*=kake
        sisuu>>=1
        kake**=2
        kake%=mod
        kotae%=mod
    return kotae

def conbi(n,r,mod):
    ue=1
    for i in range(n-r+1,n+1):
        ue*=i
        ue%=mod

    sita=1

    for i in range(1,r+1):
        sita*=i
        sita%=mod

    sita=ruizyou(sita,mod-2,mod)

    return (ue*sita)%mod

mod=10**9+7

ans=ruizyou(2,n,mod)-conbi(n,a,mod)-conbi(n,b,mod)-1
ans%=mod
print(ans)