Group()-Groups()-Groupdict().py

#Problem
"""
You are given a string S.
Your task is to find the first occurrence of an alphanumeric character in S (read from left to right) that has consecutive repetitions.
"""

#Code
import re
m = re.search(r"([a-zA-Z0-9])\1+",input())
print(m.group(1) if m else -1)