Excuse me. From which poem does the poem "After three months of war, a letter from home is worth a ton of gold" come?

spring scenery

Dynasty: Tang Dynasty

Author: Du Fu

Original text:

Chang' an fell, the country was broken, and only the mountains and rivers remained; Spring has come, and the sparsely populated Chang' an city is densely forested.

Sad state, can not help but burst into tears, amazing birds, leaving sorrow and hate.

The war lasted for more than half a year, and letters from home were rare, with a hundred thousand gold.

Twisting with melancholy, scratching my head and thinking, the more I scratch my white hair, I can hardly insert a hairpin.