I don't understand how to go about solving a problem of this form;

Integrate f(x,y,z)=x+ sqrt(y) - z^2 over the path C from (0,0,0) to (1,1,1) given by C=C1nC2uC3, where

C1: r(t)=tk , 0<t<1

C2: r(t)=tj + k , 0<t<1

C3: r(t)=ti + j + k , 0<t<1

Anyone have any suggestions??