a = input() b = input() length = [] result = {} if len(a) <= len(b): for i in range(len(a) + 1): for j in range(len(a) + 1): if a[i:j] in b: if j - i > 0: length.append(a[i:j]) else: for i in range(len(b) + 1): for j in range(len(b) + 1): if b[i:j] in a: if j - i > 0: length.append(b[i:j]) for l in length: result[l] = len(l) for k, v in result.items(): if v == max(result.values()): print(k) break