Jiang Yu, a mathematical genius, became famous at a young age, but because of the factional disputes in the academic circle, he was framed and left for Germany.
Song Ling, a small-town girl, was serving coffee in a cafe in Berchtesgaden and wanted to see the world written in the book.
She brought him a cup of coffee and saw "Kissing Number" in the title of the paper, thinking it was about kissing.
He was stunned for a moment, and then smiled - it was the first time he had laughed since coming to Germany.
Later they fell in love, returned to China together, and then separated.
She thought she could return to a peaceful life by returning to the town, but she found that after that person appeared, everyone else could only make do.
Six years later, he returned to her school to give a lecture. Standing on the stage, his eyes scanned the crowd and stopped on her face for a second.
That evening, the pigeons were still there under the old lime tree at the east end of the town.
He said: "I have missed you every day for the past six years."
This is a story about waiting. A math genius who doesn't understand the world, and a gentle but persevering small town girl, each grew up in the long separation, and then discovered that love is the most difficult and simplest question.
The end of mathematics is love.
Turning the pages of the book, you will see the snow in the Alps, pigeons under the old lime tree, and a man who has been waiting for six years.
