# D - Bouquet
n,a,b = map(int,input().split())
MOD = 10**9+7

ans = pow(2,n,MOD)-1
a,b = min(a,b),max(a,b)

tmp = 1
for i in range(1,a+1):
    tmp = tmp*(n+1-i)*pow(i,-1,MOD)
    tmp %= MOD
ans = (ans-tmp)%MOD
for i in range(a+1,b+1):
    tmp = tmp*(n+1-i)*pow(i,-1,MOD)
    tmp %= MOD
ans = (ans-tmp)%MOD

print(ans) 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 ans = pow(2,n,MOD)-1 ans pow(2,n,MOD)-1 pow(2,n,MOD) pow 2 n MOD 1 a,b = min(a,b),max(a,b) a min(a,b) min a b b max(a,b) max a b tmp = 1 tmp 1 for i in range(1,a+1):
    tmp = tmp*(n+1-i)*pow(i,-1,MOD)
    tmp %= MOD i range(1,a+1) range 1 a+1 a 1 tmp = tmp*(n+1-i)*pow(i,-1,MOD) tmp tmp*(n+1-i)*pow(i,-1,MOD) tmp*(n+1-i) tmp n+1-i n+1 n 1 i pow(i,-1,MOD) pow i -1 MOD tmp %= MOD tmp MOD ans = (ans-tmp)%MOD ans (ans-tmp)%MOD ans-tmp ans tmp MOD for i in range(a+1,b+1):
    tmp = tmp*(n+1-i)*pow(i,-1,MOD)
    tmp %= MOD i range(a+1,b+1) range a+1 a 1 b+1 b 1 tmp = tmp*(n+1-i)*pow(i,-1,MOD) tmp tmp*(n+1-i)*pow(i,-1,MOD) tmp*(n+1-i) tmp n+1-i n+1 n 1 i pow(i,-1,MOD) pow i -1 MOD tmp %= MOD tmp MOD ans = (ans-tmp)%MOD ans (ans-tmp)%MOD ans-tmp ans tmp MOD print(ans) print ans b = map(int,input().split()) map(int,input().split()) b tmp = 1 1 tmp tmp %= MOD MOD tmp ans = pow(2,n,MOD)-1 pow(2,n,MOD)-1 ans ans = (ans-tmp)%MOD (ans-tmp)%MOD ans a,b = map(int,input().split()) map(int,input().split()) a tmp %= MOD MOD tmp n,a,b = map(int,input().split()) map(int,input().split()) n a,b = min(a,b),max(a,b) min(a,b) a tmp = tmp*(n+1-i)*pow(i,-1,MOD) tmp*(n+1-i)*pow(i,-1,MOD) tmp ans = (ans-tmp)%MOD (ans-tmp)%MOD ans MOD = 10**9+7 10**9+7 MOD tmp = tmp*(n+1-i)*pow(i,-1,MOD) tmp*(n+1-i)*pow(i,-1,MOD) tmp b = min(a,b),max(a,b) max(a,b) b
# D - Bouquet
n,a,b = map(int,input().split())
MOD = 10**9+7

ans = pow(2,n,MOD)-1
a,b = min(a,b),max(a,b)

tmp = 1
for i in range(1,a+1):
    tmp = tmp*(n+1-i)*pow(i,-1,MOD)
    tmp %= MOD
ans = (ans-tmp)%MOD
for i in range(a+1,b+1):
    tmp = tmp*(n+1-i)*pow(i,-1,MOD)
    tmp %= MOD
ans = (ans-tmp)%MOD

print(ans)