Sorry not related to poker just a question thats bugging me. Need help

[StuR]

Hi,

Sorry for using this forum I thought you guys would be some of the best to ask.

In the UK in our lottery there are a possible 49 numbers and six get chosen.

Whats the minimum number of tickets I would have to buy to GUARANTEE matching at least five numbers?

I have a solution that I think may be right but I'm not sure I just wanna see what you guys can come up with.

Once again sorry if this is a problem post in a poker forum.

StuR