#yuki1237
import math
mod=10**9+7
n=int(input())
l=list(map(int,input().split()))
if 0 in l:
 print(-1)
 exit()
if max(l)>3:
 print(mod)
res=1
for i in l:
 res*=pow(i,math.factorial(i))
 if res>=mod:
  print(mod)
  exit()
print(mod%res)