import collections
a = [1, 151, 241, 1, 9, 22 , 351]
a = [str(x) for x in a]
count = collections.Counter()
seen = set()
ans = 0
for num in a:
    for i in range(len(num)):
        new_num = num[:i] + '*' + num[i+1:]
        if num not in seen and new_num in count:
            ans += count[new_num]
        count[new_num] += 1
    seen.add(num)

print(ans)