Prompt: On this particular day, a fierce north wind howled, and heavy snowfall made the journey unbearably cold. Zhang Fei protested loudly to Liu Bei, \"Why should we endure such hardship? Let's wait for fair weather.\" Liu Bei responded, \"Dear brother, by braving this snowstorm and enduring the difficult mountainous roads to invite Zhuge Liang, aren't we demonstrating our sincere intentions?\" The three continued their journey. Unexpectedly, Liu Bei once again missed Zhuge Liang at Longzhong, leading him to write a letter entrusting Zhuge Liang's younger brother to convey his purpose and expressing his intention to visit again.