"""
Let's teach the Robots to distinguish words and numbers.

You are given a string with words and numbers separated by whitespaces (one space). The words contains only letters. You should check if the string contains three words in succession . For example, the string "start 5 one two three 7 end" contains three words in succession.

Input: A string with words.

Output: The answer as a boolean.

Example:
1 checkio("Hello World hello") == True
2 checkio("He is 123 man") == False
3 checkio("1 2 3 4") == False
4 checkio("bla bla bla bla") == True
5 checkio("Hi") == False

How it is used: This teaches you how to work with strings and introduces some useful functions.

Precondition: The input contains words and/or numbers. There are no mixed words (letters and digits combined).
0 < len(words) < 100
"""

def checkio(words: str) -> bool:
    output = False
    words = words.split()
    if len(words) >= 3:
        for i in range(len(words)-2):
            if words[i].isalpha() and words[i+1].isalpha() and words[i+2].isalpha():
                output = True
    return output

print('Tests:')
print(checkio("Hello World hello"))
print(checkio("He is 123 man"))
print(checkio("1 2 3 4"))
print(checkio("bla bla bla bla"))
print(checkio("Hi"))