MOD = 10**9+7
n,a,b=map(int, input().split())
ca = 1
cb = 1
for i in range(n-a+1,n+1):
    ca *= i
    ca%=MOD
for i in range(1,a+1):
    ca *= (pow(i,MOD-2,MOD))
    ca%=MOD
for i in range(n-b+1,n+1):
    cb *= i
    cb%=MOD
for i in range(1,b+1):
    cb*=(pow(i,MOD-2,MOD))
    cb%=MOD
print((pow(2,n,MOD)-1-ca-cb)%MOD) MOD = 10**9+7 MOD 10**9+7 10**9 10 9 7 n,a,b=map(int, input().split()) n map(int, input().split()) map int input().split() ().split () input split a b ca = 1 ca 1 cb = 1 cb 1 for i in range(n-a+1,n+1):
    ca *= i
    ca%=MOD i range(n-a+1,n+1) range n-a+1 n-a n a 1 n+1 n 1 ca *= i ca i ca%=MOD ca MOD for i in range(1,a+1):
    ca *= (pow(i,MOD-2,MOD))
    ca%=MOD i range(1,a+1) range 1 a+1 a 1 ca *= (pow(i,MOD-2,MOD)) ca pow(i,MOD-2,MOD) pow i MOD-2 MOD 2 MOD ca%=MOD ca MOD for i in range(n-b+1,n+1):
    cb *= i
    cb%=MOD i range(n-b+1,n+1) range n-b+1 n-b n b 1 n+1 n 1 cb *= i cb i cb%=MOD cb MOD for i in range(1,b+1):
    cb*=(pow(i,MOD-2,MOD))
    cb%=MOD i range(1,b+1) range 1 b+1 b 1 cb*=(pow(i,MOD-2,MOD)) cb pow(i,MOD-2,MOD) pow i MOD-2 MOD 2 MOD cb%=MOD cb MOD print((pow(2,n,MOD)-1-ca-cb)%MOD) print (pow(2,n,MOD)-1-ca-cb)%MOD pow(2,n,MOD)-1-ca-cb pow(2,n,MOD)-1-ca pow(2,n,MOD)-1 pow(2,n,MOD) pow 2 n MOD 1 ca cb MOD ca%=MOD MOD ca ca *= i i ca MOD = 10**9+7 10**9+7 MOD ca%=MOD MOD ca ca *= (pow(i,MOD-2,MOD)) pow(i,MOD-2,MOD) ca cb *= i i cb n,a,b=map(int, input().split()) map(int, input().split()) n cb = 1 1 cb a,b=map(int, input().split()) map(int, input().split()) a cb%=MOD MOD cb cb*=(pow(i,MOD-2,MOD)) pow(i,MOD-2,MOD) cb cb%=MOD MOD cb b=map(int, input().split()) map(int, input().split()) b ca = 1 1 ca
MOD = 10**9+7
n,a,b=map(int, input().split())
ca = 1
cb = 1
for i in range(n-a+1,n+1):
    ca *= i
    ca%=MOD
for i in range(1,a+1):
    ca *= (pow(i,MOD-2,MOD))
    ca%=MOD
for i in range(n-b+1,n+1):
    cb *= i
    cb%=MOD
for i in range(1,b+1):
    cb*=(pow(i,MOD-2,MOD))
    cb%=MOD
print((pow(2,n,MOD)-1-ca-cb)%MOD)
