N=int(input())
mod=998244353
A=list(map(int,input().split()))
ans=1
for i in range(N):
  this=1
  for j in range(N):
    if i!=j:
      this*=(A[i]**2-A[j]**2)
    else:
      this*=A[i]
    this%=mod
  ans+=pow(this,-1,mod)
  ans%=mod
if i%2==0:
  print((ans-1)%mod)
else:
  print(-ans%mod)