def to_uppercase(str1):  
    num_upper = 0  
    for letter in str1[:4]:   
        if letter.upper() == letter:  
            num_upper += 1  
    if num_upper >= 2:  
        return str1.upper()  
    return str1  
  
print(to_uppercase('Python'))  
print(to_uppercase('PyThon')) 