from functools import lru_cache


@lru_cache(None)
def lcs(s1, s2, s1pos=None, s2pos=None):
    if s1pos is None:
        print(f"<1>: {len(s1) - 1}")
        s1pos = len(s1) - 1
    if s2pos is None:
        print(f"<2>: {len(s2) - 1}")
        s2pos = len(s2) - 1

    if s1pos < 0 or s2pos < 0:
        return 0
    elif s1[s1pos] == s2[s2pos]:
        return 1 + max(lcs(s1, s2, s1pos=s1pos-1, s2pos=s2pos), lcs(s1, s2, s1pos=s1pos, s2pos=s2pos-1))
    else:
        return max(lcs(s1, s2, s1pos=s1pos-1, s2pos=s2pos), lcs(s1, s2, s1pos=s1pos, s2pos=s2pos-1))


print(lcs('wekomfiowefmeowijfiowmfoiewmfoiwemfoiew',
          'vewoijfioewfmncoqwimfcoweifnewiufnwiefcmnwiu'))
print(lcs.cache_info())