n,a,b = [int(x) for x in input().split()]



ans = 0

mod = 10**9+7

ans = (pow(2,n,mod)-1)%mod



com1 = 1

for i in range(n-a+1,n+1):

    com1 = com1*i%mod

for i in range(1,a+1):

    com1 = com1 * pow(i,mod-2,mod)%mod

com2 = 1

for i in range(n-b+1,n+1):

    com2 = com2*i%mod

for i in range(1,b+1):

    com2 = com2*pow(i,mod-2,mod)%mod

ans = (ans - com1 - com2)%mod

print(ans)
n,a,b = [int(x) for x in input().split()]



ans = 0

mod = 10**9+7

ans = (pow(2,n,mod)-1)%mod



com1 = 1

for i in range(n-a+1,n+1):

    com1 = com1*i%mod

for i in range(1,a+1):

    com1 = com1 * pow(i,mod-2,mod)%mod

com2 = 1

for i in range(n-b+1,n+1):

    com2 = com2*i%mod

x = 1

for i in range(1,b+1):

    x = x*i%mod

com2 = com2*pow(x,mod-2,mod)%mod



ans = (ans - com1 - com2)%mod

print(ans)
n, a, b = [int(x) for x in input().split()]
ans = 0
mod = 10**9 + 7
ans = (pow(2, n, mod) - 1) % mod
com1 = 1
for i in range(n - a + 1, n + 1):
    com1 = com1 * i % mod
for i in range(1, a + 1):
    com1 = com1 * pow(i, mod - 2, mod) % mod
com2 = 1
for i in range(n - b + 1, n + 1):
    com2 = com2 * i % mod
for i in range(1, b + 1):
    com2 = com2 * pow(i, mod - 2, mod) % mod
ans = (ans - com1 - com2) % mod
print(ans)

n, a, b = [int(x) for x in input().split()]
ans = 0
mod = 10**9 + 7
ans = (pow(2, n, mod) - 1) % mod
com1 = 1
for i in range(n - a + 1, n + 1):
    com1 = com1 * i % mod
for i in range(1, a + 1):
    com1 = com1 * pow(i, mod - 2, mod) % mod
com2 = 1
for i in range(n - b + 1, n + 1):
    com2 = com2 * i % mod
x = 1
for i in range(1, b + 1):
    x = x * i % mod
com2 = com2 * pow(x, mod - 2, mod) % mod
ans = (ans - com1 - com2) % mod
print(ans)

+x = 1 -    com2 = com2 * pow(i, mod - 2, mod) % mod +    x = x * i % mod +com2 = com2 * pow(x, mod - 2, mod) % mod