def cmb(a,b,c):
    b = min(b,a-b)
    num = 1
    for i in range(b):
        num = num*(n-i) % c
    den = 1
    for i in range(b):
        den = den*(i+1) % c
    return num*pow(den,c-2,c) % c
mod = 10**9+7
n,a,b = map(int,input().split())
ans  = (pow(2,n,mod)-cmb(n,a,mod)-cmb(n,b,mod)-1) % mod
if ans < 0:
    ans = ans + mod
print(ans) def cmb(a,b,c):
    b = min(b,a-b)
    num = 1
    for i in range(b):
        num = num*(n-i) % c
    den = 1
    for i in range(b):
        den = den*(i+1) % c
    return num*pow(den,c-2,c) % c cmb b = min(b,a-b) b min(b,a-b) min b a-b a b num = 1 num 1 for i in range(b):
        num = num*(n-i) % c
     i range(b) range b num = num*(n-i) % c num num*(n-i) % c num*(n-i) num n-i n i c den = 1 den 1 for i in range(b):
        den = den*(i+1) % c
     i range(b) range b den = den*(i+1) % c den den*(i+1) % c den*(i+1) den i+1 i 1 c return num*pow(den,c-2,c) % c num*pow(den,c-2,c) % c num*pow(den,c-2,c) num pow(den,c-2,c) pow den c-2 c 2 c c a a b b c c 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 ans  = (pow(2,n,mod)-cmb(n,a,mod)-cmb(n,b,mod)-1) % mod ans (pow(2,n,mod)-cmb(n,a,mod)-cmb(n,b,mod)-1) % mod pow(2,n,mod)-cmb(n,a,mod)-cmb(n,b,mod)-1 pow(2,n,mod)-cmb(n,a,mod)-cmb(n,b,mod) pow(2,n,mod)-cmb(n,a,mod) pow(2,n,mod) pow 2 n mod cmb(n,a,mod) cmb n a mod cmb(n,b,mod) cmb n b mod 1 mod if ans < 0:
    ans = ans + mod ans < 0 ans 0 ans = ans + mod ans ans + mod ans mod print(ans) print ans ans = ans + mod ans + mod ans def cmb(a,b,c):
    b = min(b,a-b)
    num = 1
    for i in range(b):
        num = num*(n-i) % c
    den = 1
    for i in range(b):
        den = den*(i+1) % c
    return num*pow(den,c-2,c) % c def cmb(a,b,c):
    b = min(b,a-b)
    num = 1
    for i in range(b):
        num = num*(n-i) % c
    den = 1
    for i in range(b):
        den = den*(i+1) % c
    return num*pow(den,c-2,c) % c cmb mod = 10**9+7 10**9+7 mod b = map(int,input().split()) map(int,input().split()) b a,b = map(int,input().split()) map(int,input().split()) a ans  = (pow(2,n,mod)-cmb(n,a,mod)-cmb(n,b,mod)-1) % mod (pow(2,n,mod)-cmb(n,a,mod)-cmb(n,b,mod)-1) % mod ans n,a,b = map(int,input().split()) map(int,input().split()) n
def cmb(a,b,c):
    b = min(b,a-b)
    num = 1
    for i in range(b):
        num = num*(n-i) % c
    den = 1
    for i in range(b):
        den = den*(i+1) % c
    return num*pow(den,c-2,c) % c
mod = 10**9+7
n,a,b = map(int,input().split())
ans  = (pow(2,n,mod)-cmb(n,a,mod)-cmb(n,b,mod)-1) % mod
if ans < 0:
    ans = ans + mod
print(ans)