#

import sys
input=sys.stdin.readline
MOD=10**9+7

def main():
    n,a,b=map(int,input().split())
    nca=1
    for i in range(a):
        nca=(nca*(n-i))%MOD
    for i in range(a):
        nca=(nca*pow(i+1,MOD-2,MOD))%MOD
    ncb=1
    for i in range(b):
        ncb=(ncb*(n-i))%MOD
    for i in range(b):
        ncb=(ncb*pow(i+1,MOD-2,MOD))%MOD
    print((pow(2,n,MOD)-1-nca-ncb)%MOD)
    
    
    
if __name__=="__main__":
    main() import sys sys input=sys.stdin.readline input sys.stdin.readline sys.stdin sys stdin readline MOD=10**9+7 MOD 10**9+7 10**9 10 9 7 def main():
    n,a,b=map(int,input().split())
    nca=1
    for i in range(a):
        nca=(nca*(n-i))%MOD
    for i in range(a):
        nca=(nca*pow(i+1,MOD-2,MOD))%MOD
    ncb=1
    for i in range(b):
        ncb=(ncb*(n-i))%MOD
    for i in range(b):
        ncb=(ncb*pow(i+1,MOD-2,MOD))%MOD
    print((pow(2,n,MOD)-1-nca-ncb)%MOD)
    
    
     main n,a,b=map(int,input().split()) n map(int,input().split()) map int input().split() ().split () input split a b nca=1 nca 1 for i in range(a):
        nca=(nca*(n-i))%MOD
     i range(a) range a nca=(nca*(n-i))%MOD nca (nca*(n-i))%MOD nca*(n-i) nca n-i n i MOD for i in range(a):
        nca=(nca*pow(i+1,MOD-2,MOD))%MOD
     i range(a) range a nca=(nca*pow(i+1,MOD-2,MOD))%MOD nca (nca*pow(i+1,MOD-2,MOD))%MOD nca*pow(i+1,MOD-2,MOD) nca pow(i+1,MOD-2,MOD) pow i+1 i 1 MOD-2 MOD 2 MOD MOD ncb=1 ncb 1 for i in range(b):
        ncb=(ncb*(n-i))%MOD
     i range(b) range b ncb=(ncb*(n-i))%MOD ncb (ncb*(n-i))%MOD ncb*(n-i) ncb n-i n i MOD for i in range(b):
        ncb=(ncb*pow(i+1,MOD-2,MOD))%MOD
     i range(b) range b ncb=(ncb*pow(i+1,MOD-2,MOD))%MOD ncb (ncb*pow(i+1,MOD-2,MOD))%MOD ncb*pow(i+1,MOD-2,MOD) ncb pow(i+1,MOD-2,MOD) pow i+1 i 1 MOD-2 MOD 2 MOD MOD print((pow(2,n,MOD)-1-nca-ncb)%MOD) print (pow(2,n,MOD)-1-nca-ncb)%MOD pow(2,n,MOD)-1-nca-ncb pow(2,n,MOD)-1-nca pow(2,n,MOD)-1 pow(2,n,MOD) pow 2 n MOD 1 nca ncb MOD if __name__=="__main__":
    main() __name__=="__main__" __name__ "__main__" main() main def main():
    n,a,b=map(int,input().split())
    nca=1
    for i in range(a):
        nca=(nca*(n-i))%MOD
    for i in range(a):
        nca=(nca*pow(i+1,MOD-2,MOD))%MOD
    ncb=1
    for i in range(b):
        ncb=(ncb*(n-i))%MOD
    for i in range(b):
        ncb=(ncb*pow(i+1,MOD-2,MOD))%MOD
    print((pow(2,n,MOD)-1-nca-ncb)%MOD)
    
    
     def main():
    n,a,b=map(int,input().split())
    nca=1
    for i in range(a):
        nca=(nca*(n-i))%MOD
    for i in range(a):
        nca=(nca*pow(i+1,MOD-2,MOD))%MOD
    ncb=1
    for i in range(b):
        ncb=(ncb*(n-i))%MOD
    for i in range(b):
        ncb=(ncb*pow(i+1,MOD-2,MOD))%MOD
    print((pow(2,n,MOD)-1-nca-ncb)%MOD)
    
    
     main MOD=10**9+7 10**9+7 MOD input=sys.stdin.readline sys.stdin.readline input
#

import sys
input=sys.stdin.readline
MOD=10**9+7

def main():
    n,a,b=map(int,input().split())
    nca=1
    for i in range(a):
        nca=(nca*(n-i))%MOD
    for i in range(a):
        nca=(nca*pow(i+1,MOD-2,MOD))%MOD
    ncb=1
    for i in range(b):
        ncb=(ncb*(n-i))%MOD
    for i in range(b):
        ncb=(ncb*pow(i+1,MOD-2,MOD))%MOD
    print((pow(2,n,MOD)-1-nca-ncb)%MOD)
    
    
    
if __name__=="__main__":
    main()
