import bisect
from itertools import permutations
from collections import Counter
MOD = 998244353
N = int(input())
C = list(map(int,input().split()))

"""
def count(C):
    cc = Counter(C)
    for i in list(cc.keys()):
        cc[i] %= 2
    return sum(cc.values())

from random import randint
while(True):
    N = 2*10**5
    C = [randint(1,9) for _ in range(N)]
    print(count(C))
"""

CC = Counter(C)
for i in list(CC.keys()):
    CC[i] %= 2
    if(CC[i] == 0):CC.pop(i)
nokori = []
for i in CC:
    for _ in range(CC[i]):
        nokori.append(i)

def can_make(S):
    ret = [-1,10**18]
    for i in permutations(map(str,S)):
        ret.append(int("".join(i)))
    return sorted(ret)

N = len(nokori)
if(N == 0):
    print(0)
    exit()

ans = 10**18
for i in range(1,1<<N-1):
    a,b = [],[]
    for j in range(N):
        if(i>>j & 1 == 0):
            a.append(nokori[j])
        else:
            b.append(nokori[j])
    
    ca = can_make(a)
    cb = can_make(b)
    
    for i in ca[1:-1]:
        left = bisect.bisect_right(cb,i) - 1
        right = bisect.bisect_left(cb,i)
        
        ans = min(ans, abs(i - cb[left]), abs(i - cb[right]))
print(ans % MOD)