n = int(input())
t = list(map(int,input().split()))
s = [1,0,1,0,1,1,0,1,0,1,0,1]
l = [0] * 12
v = []
for i in t:
    l[i] = 1

print(" l",l)
for i in range(12):
    u = [x*y for (x,y) in zip(l,s)]
    if u == l:
        print(str(i).zfill(2),s)
        v.append(i)
    s.insert(0,s.pop(-1))    

if len(v) == 1:
    print(v[0])
else:
    print(-1)