Which is a safe coin to invest in the long term?
How long should I hold it?
Is there a risk that I might lose it all?
I am a noob in cryptocurrencies. Help.

I was thinking Litecoin, is it a good idea?
You should research first to start an investment, do not spend any money on coins that can not grow. there are so many coins in the crypto, you might choose altcoins like ethereum, neo or litecoin.