Could I get some help on pre-calc?

What is the maximum possible length of the vector resulting from the following linear combination?
\({1\over{||v_1||}}v_1+{1\over{||v_2||}}v_2+\cdot\cdot\cdot+{1\over{||v_n||}}v_n\)                                                       [how to do vectors... :(]

Thanks team!