How can I find unique values in column ?

This is my matrix

m=
     1    10
     2     1
     2     2
     2     3
     2     4
     3     1
     3     2
     3     3
     5     1
     5     2
     5     4
     6     2

I want to unique first column and second one can be anything among own values. I want to something like that

     1    10
     2     1
     3     2
     5     4
     6     2

P.S I tried "unique" code it didnt work

Answer 1

[Azzi Abdelmalek]

[~,b]=unique(m(:,1),'stable')
out=m(b,:)

If you want to choose the second column randomly

[~,~,c]=unique(m(:,1),'stable')
ii=accumarray(c,(1:numel(c))',[],@(x) x(randi(numel(x))))
out=m(ii,:)

[Selin Ozdemir]

Thank you so much