n=int(input())
for i in range(n):
num=int(input())
l=list(input().split())
if ord(l[-1])>ord(l[-2]):
temp=l[-1]
l[-1]=l[-2]
l[-2]=temp
s=''
print(int(s.join(l)))
else:
j=num-2
while True:
if ord(l[j])>ord(l[j-1]):
new=[h for h in l[j:num]]
new.sort()
length=len(new)
for k in range(length):
if ord(new[k])>ord(l[j-1]):
temp=new[k]
new[k]=l[j-1]
l[j-1]=temp
bana=[f for f in l[0:j]]+[m for m in new]
s=''
print(int(s.join(bana)))
break
break
else:
if ord(l[j])<=ord(l[j-1]) and j!=1:
pass
else:
print(-1)
break
j=j-1