import sys,collections,math
input = sys.stdin.readline

n,a,b = list(map(int,input().split()))
m = 10**9+7
ans = pow(2,n,m)


la  = 1
laa = 1
for i in range(n,n-a,-1):
    la = (la*i)%m
for i in range(1,a+1):
    laa = (laa*i)%m

lb  = 1
lbb = 1
for i in range(n,n-b,-1):
    lb = (lb*i)%m
for i in range(1,b+1):
    lbb = (lbb*i)%m

la = (la*pow(laa,10**9+5,m))%m
lb = (lb*pow(lbb,10**9+5,m))%m

print((ans-la-lb-1)%m) import sys,collections,math sys collections math input = sys.stdin.readline input sys.stdin.readline sys.stdin sys stdin readline n,a,b = list(map(int,input().split())) n list(map(int,input().split())) list map(int,input().split()) map int input().split() ().split () input split a b m = 10**9+7 m 10**9+7 10**9 10 9 7 ans = pow(2,n,m) ans pow(2,n,m) pow 2 n m la  = 1 la 1 laa = 1 laa 1 for i in range(n,n-a,-1):
    la = (la*i)%m i range(n,n-a,-1) range n n-a n a -1 la = (la*i)%m la (la*i)%m la*i la i m for i in range(1,a+1):
    laa = (laa*i)%m i range(1,a+1) range 1 a+1 a 1 laa = (laa*i)%m laa (laa*i)%m laa*i laa i m lb  = 1 lb 1 lbb = 1 lbb 1 for i in range(n,n-b,-1):
    lb = (lb*i)%m i range(n,n-b,-1) range n n-b n b -1 lb = (lb*i)%m lb (lb*i)%m lb*i lb i m for i in range(1,b+1):
    lbb = (lbb*i)%m i range(1,b+1) range 1 b+1 b 1 lbb = (lbb*i)%m lbb (lbb*i)%m lbb*i lbb i m la = (la*pow(laa,10**9+5,m))%m la (la*pow(laa,10**9+5,m))%m la*pow(laa,10**9+5,m) la pow(laa,10**9+5,m) pow laa 10**9+5 10**9 10 9 5 m m lb = (lb*pow(lbb,10**9+5,m))%m lb (lb*pow(lbb,10**9+5,m))%m lb*pow(lbb,10**9+5,m) lb pow(lbb,10**9+5,m) pow lbb 10**9+5 10**9 10 9 5 m m print((ans-la-lb-1)%m) print (ans-la-lb-1)%m ans-la-lb-1 ans-la-lb ans-la ans la lb 1 m ans = pow(2,n,m) pow(2,n,m) ans lb = (lb*pow(lbb,10**9+5,m))%m (lb*pow(lbb,10**9+5,m))%m lb b = list(map(int,input().split())) list(map(int,input().split())) b lb  = 1 1 lb laa = (laa*i)%m (laa*i)%m laa n,a,b = list(map(int,input().split())) list(map(int,input().split())) n laa = 1 1 laa lbb = (lbb*i)%m (lbb*i)%m lbb lbb = 1 1 lbb a,b = list(map(int,input().split())) list(map(int,input().split())) a input = sys.stdin.readline sys.stdin.readline input la = (la*pow(laa,10**9+5,m))%m (la*pow(laa,10**9+5,m))%m la lb = (lb*i)%m (lb*i)%m lb m = 10**9+7 10**9+7 m la  = 1 1 la la = (la*i)%m (la*i)%m la
import sys,collections,math
input = sys.stdin.readline

n,a,b = list(map(int,input().split()))
m = 10**9+7
ans = pow(2,n,m)


la  = 1
laa = 1
for i in range(n,n-a,-1):
    la = (la*i)%m
for i in range(1,a+1):
    laa = (laa*i)%m

lb  = 1
lbb = 1
for i in range(n,n-b,-1):
    lb = (lb*i)%m
for i in range(1,b+1):
    lbb = (lbb*i)%m

la = (la*pow(laa,10**9+5,m))%m
lb = (lb*pow(lbb,10**9+5,m))%m

print((ans-la-lb-1)%m)
