mod = 10**9 + 7
n, a, b = map(int, input().split())
res = pow(2, n, mod)-1

c1 = 1
for i in range(n-a+1, n+1):
    c1 *= i
    c1 %= mod

for i in range(1, a+1):
    c1 *= pow(i, mod-2, mod)
    c1 %= mod
    
c2 = 1
for i in range(n-b+1, n+1):
    c2 *= i
    c2 %= mod

for i in range(1, b+1):
    c2 *= pow(i, mod-2, mod)
    c2 %= mod
    
res -= (c1+c2)
res %= mod
print(res) 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 res = pow(2, n, mod)-1 res pow(2, n, mod)-1 pow(2, n, mod) pow 2 n mod 1 c1 = 1 c1 1 for i in range(n-a+1, n+1):
    c1 *= i
    c1 %= mod i range(n-a+1, n+1) range n-a+1 n-a n a 1 n+1 n 1 c1 *= i c1 i c1 %= mod c1 mod for i in range(1, a+1):
    c1 *= pow(i, mod-2, mod)
    c1 %= mod
     i range(1, a+1) range 1 a+1 a 1 c1 *= pow(i, mod-2, mod) c1 pow(i, mod-2, mod) pow i mod-2 mod 2 mod c1 %= mod c1 mod c2 = 1 c2 1 for i in range(n-b+1, n+1):
    c2 *= i
    c2 %= mod i range(n-b+1, n+1) range n-b+1 n-b n b 1 n+1 n 1 c2 *= i c2 i c2 %= mod c2 mod for i in range(1, b+1):
    c2 *= pow(i, mod-2, mod)
    c2 %= mod
     i range(1, b+1) range 1 b+1 b 1 c2 *= pow(i, mod-2, mod) c2 pow(i, mod-2, mod) pow i mod-2 mod 2 mod c2 %= mod c2 mod res -= (c1+c2) res c1+c2 c1 c2 res %= mod res mod print(res) print res n, a, b = map(int, input().split()) map(int, input().split()) n c1 *= i i c1 c2 = 1 1 c2 c1 %= mod mod c1 res = pow(2, n, mod)-1 pow(2, n, mod)-1 res c2 %= mod mod c2 res -= (c1+c2) c1+c2 res a, b = map(int, input().split()) map(int, input().split()) a c1 = 1 1 c1 c1 %= mod mod c1 c2 %= mod mod c2 mod = 10**9 + 7 10**9 + 7 mod res %= mod mod res b = map(int, input().split()) map(int, input().split()) b c1 *= pow(i, mod-2, mod) pow(i, mod-2, mod) c1 c2 *= pow(i, mod-2, mod) pow(i, mod-2, mod) c2 c2 *= i i c2
mod = 10**9 + 7
n, a, b = map(int, input().split())
res = pow(2, n, mod)-1

c1 = 1
for i in range(n-a+1, n+1):
    c1 *= i
    c1 %= mod

for i in range(1, a+1):
    c1 *= pow(i, mod-2, mod)
    c1 %= mod
    
c2 = 1
for i in range(n-b+1, n+1):
    c2 *= i
    c2 %= mod

for i in range(1, b+1):
    c2 *= pow(i, mod-2, mod)
    c2 %= mod
    
res -= (c1+c2)
res %= mod
print(res)