

A shocking video shows school students in Russia laughing as a screaming woman desperately clings on for her life from a third floor window.
The footage shows the woman, 50, desperately pleading for help as she dangles from her fingertips on the side of a tall building in Tatarstan.
But the teenagers do not call for help, instead using a mobile phone to film the person.
On the footage a boy is heard asking 'isn't it funny?', sparking a media and online backlash.
The students are laughing so hard that the mobile used to film the incident can be seen constantly shaking.
Eventually the frightened woman fell to the ground, and is now seriously injured in hospital.
The video was later uploaded to YouTube.
Pro-Kremlin newspaper Komsomolskaya Pravda blasted the reaction of the witnesses to the 'tragedy' in Zainsk town.
'She was filmed and laughed at,' said the report.
'The woman was hanging from the balcony of the third floor and screaming for help - but nobody rushed to aid her, neither witnesses, nor the neighbour from the lower flat.
'There were several witnesses.
'Their behaviour was surprising and negative.'
Doctors at the hospital, where she was treated, said she had 'numerous injuries, mainly broken bones, and is facing several surgeries'.
It was not clear why the woman was hanging from the balcony.
The footage has prompted a backlash from angry commenters online.
'Idiots! One day they will need help too. And they will remember what they were doing when someone else needed their assistance,' wrote one person.
A reader said: 'They could have found some blanket and held it so she could jump down. Don't they have safety lessons at school?'
Another wrote: 'This is the generation of gadgets and smartphones, but just look at them. If you can't do anything, just call an ambulance.'
One commenter said: 'This brings horrible feelings. I am sick from human heartlessness. Are they people?'
Another said: 'This behaviour from our youth. Where do we get such people?'
'It is sad and scary to living in such a society.'
Another demanded: 'They could have stood on each others shoulders and saved the woman.'