Sweat dripping from her forehead, teacher Li Yufen slowly walked up the stairs to the second floor of her building. On her back was Fan Yu, a 9-year-old pupil who suffers from congenital heart disease.

It is a scene that has taken place many times over the last two years at Tianxin Elementary School near Lianzhou, Guangdong province, where Li is well known as "the teacher with a loving heart".

There are only four grades in the school, so pupils then have to find somewhere else to study.

With the number of births going down in recent years, the number of school-age pupils has also dived from more than 60 a decade ago to only one, Fan Yu, over the last year.

"But this school is the symbol of the village's hope and prestige," says village head Zhao Mugen. "More than 10 students have gone to college in the last 10 years, while the teachers have also left one by one, leaving only Li."

According to the curriculum, Fan has four classes in the morning and two more in the afternoon - including Chinese, maths, English, arts and music. "She cannot have PE classes due to her weak health condition," says Li.

Fan is now in second grade and although she belongs to an ethnic group, she can speak standard Mandarin. "I was taught by my teacher," says the little girl, adding that her happiest moments during the day are in class, since teacher Li is an excellent story-teller.

Besides her weak health, Fan also has a poverty-stricken background. Her mother abandoned the family shortly after Fan's birth, her father and grandfather have left the village for work and she is now cared for by her 60-year-old grandmother.

Though most students have gone to other schools, Li Yufen still stays to teach her only student, who suffers from congenital heart disease, in a mountainous village in Guangdong.

In villagers' eyes, Li is actually as much a baby-sitter as teacher. She carries Fan on her back when she goes upstairs. She heats up food for her, puts more clothes on her in winter and prevents heatstroke in the summer. Even after school, Fan is taken home by Li's husband on his motorbike.

"It is difficult to find another teacher as good as Li," says Zhao.