PromptCode/1

def cg(intervals: list[tuple[int, int]]) -> int:
    if len(intervals) <= 1:
        return 0

    sorted_intervals = sorted(intervals, key=lambda x: (x[0], x[1]))

    merged = [sorted_intervals[0]]
    for start, end in sorted_intervals[1:]:
        prev_start, prev_end = merged[-1]
        if start < prev_end:  # strictly less: touching intervals are NOT merged
            merged[-1] = (prev_start, max(prev_end, end))
        else:
            merged.append((start, end))

    return len(merged) - 1