Oṁ Saha nāvavatu, saha nau bhunaktu 

Oh Lord please protect both of us, let us both enjoy

Saha vīryam karavāvahai, Tejasvi nāvadhītamastu

Let us put forth the right effort, let our learning be brilliant

Mā vidviṣāvahai..Oṁ Shāntiḥ, Shāntiḥ, Shāntiḥ

Let there be no conflict between both of us.The last three Shanti chants represent the removal of the 3 obstacles:
1 --- obstacles that come from our unknown sources, which we have no control over.
2 --- obstacles being those that come from the world around us.
3 --- obstacles being those that come from within oneself (body and mind).

* This Mantra is taken from the Krishna Yajurveda Taittiriya Upanishad (2.2.2)