binsearch()

bin.py

#!/usr/bin/env python3

nums = sorted([int(x) for x in input().split()])

def search(x):
    # low <= i < high
    def binsearch(i, low, high):
        if i == low or nums[i] == x:
            return i 
        return binsearch((low + i)//2, low, i) if x <nums[i] else binsearch((i+high)//2, i, high)

    i = binsearch(len(nums)//2, 0, len(nums))
    return f'{x} found at index {i}' if nums[i] == x else f'{x} not found'

print(search(3))