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Leaving Mars

The spacecraft is designed to leave the surface of Mars with the first stage of its propulsion system and be put into Martian orbit. Then, the second stage is used to boost the spacecraft from Martian orbit into an interplanetary trajectory and return to Earth.

If the spacecraft is in Martian orbit at an altitude of 341 km, what is the velocity (in km/s) required to escape the gravitational attraction of Mars. Note that the velocity direction and magnitude required to actually return to Earth may be different.

My work so far:

Mass of Mars (Mp): 6.392E23

Radius of Mars (R): 3.395E6

<---correct equation

my answer came to 5.012761026 which is not right according to the electronic answering system in which the homework is completed on.

also if you can show me how to solve it on a graphing calculator

thanks for the help!!!!!