Please help and thank you. I am not sure what least integral value means in this question.

least integral value means the smallest value of m which is also an integer.

in our case, we can write [(1+i)/(1 – i)]^m= 1

or [(1+i)^2/(1 – i)(1+i)]^m= 1

or (2i/2)^m= 1

or i^m= 1

now, least integral value of m can be as less as we want, so question is wrong. the correct question should be to find the least positive integral value of m, which will obviously be m= 4