def merge_the_tools(string, k):
    for i in range(0, len(string), k):  # Split into k-sized substrings
        substring = string[i:i + k]
        seen = set()
        result = ""
        for char in substring:
            if char not in seen:  # Preserve order, remove duplicates
                seen.add(char)
                result += char
        print(result)