#N=int(input())
N,A,B=map(int,input().split())
#A=list(map(int, input().split()))
mod=998244353 
C=[1]
for i in range(1,N+1):
  C.append(C[-1]*i%mod)
if A!=B:
  ans=C[-1]-(C[-2]+C[-2]-C[-3])
  print(ans%mod)
else:
  ans=C[-1]-(C[-2]+C[-2])
  print(ans%mod)