ch = int(input())

brk_n = int(input())

brk_btn = list()

if brk_n!=0:

brk_btn = input().split()

min_cnt = abs(100-ch)

for i in range(500000):

if i > min_cnt:

break

pcheck = True

mcheck = True

if brk_btn:

if ch-i>=0:

for btn in brk_btn:

if btn in str(ch - i):

mcheck = False

break

else:

mcheck = False

for btn in brk_btn:

if btn in str(ch + i):

pcheck = False

break

if mcheck:

min_cnt = min(min_cnt, i + len(str(ch - i)))

break

if pcheck:

min_cnt = min(min_cnt, i + len(str(ch+i)))

break

print(min_cnt)