Assignment of a string to an empty matrix

I have a script that's supposed to assign a random name from a list. The script calls on a function to pick the name, and the function works fine. When I try to assign the name, it gives me the following error: "Unable to perform assignment because the indices on the left side are not compatible with the size of the right side." The problem is in the first FOR loop under the %% Pick Teams header: Teams{aa}(bb) = new_name; Here's my whole script>>

filename = input('Enter student list file name:','s');
team_size = input('Enter number of students per team:');

%%Import Data

names = textread(filename,'%s %*s','headerlines',1);

%%Pre-allocate Teams cell

n_names = length(names);
n_teams = round(n_names/team_size);
Teams = cell(n_teams,1);

%%Pick Teams

for aa = 1:team_size
    for bb = 1:team_size
        new_name = pick_names(names);
        Teams{aa}(bb) = new_name;
    end
end

%%Team for Extras

n_extras = rem(n_names,team_size);
for aa = 1:n_extras
    new_name = pick_names(names);
    Teams{n_teams+1}(aa) = new_name;
end    

%%Display Teams
for aa = 1:length(names)
    fprintf('Members of Team %d: \n',aa)
    disp(char(Teams{aa}))
end

Any help is greatly appreciated!!

[Bob Thompson]

If I am not mistaken then your indexing of Teams{aa}(bb) calls a specific element of cell aa within Teams. This is acceptable, but using parentheses indicates that bb by default is a numerical or logical element, and therefore cannot receive a string. Try

 Teams{aa}{bb} = new_name;