Probability calculation with Naive Bayes Probability Density Function by hand

veri = readtable ('gh.csv');

vericell = table2cell(veri);

ghcolumn = cell2mat(vericell(:,3));

veri.Class = discretize(veri{:, 3}, min(veri{:, 3}):29:max(veri{:, 3})+29); %with this column I am seperating my dataset into classes with intervals according to 3rd column of my dataset.

vericell = table2cell(veri);

class = cell2mat(vericell(:,end));

for ii=min(veri.Class):max(veri.Class)

    deneme{ii,:}=vericell (class==ii,:);
    deneme{ii,:}=cell2table(deneme{ii});
end
vericell = cell2table(vericell);
predictioncolumn = readtable("predictioncolumn.csv");
predictioncolumn = table2array(predictioncolumn);
for ii=min(veri.Class):max(veri.Class)
    deneme{ii,:}= vericell(class==ii,:);
        for j = 4:14    
             deneme{ii}{:,j};
        end
        for kk = min(veri.Class):max(veri.Class)
            for s = 4:14
             meanres(kk,s) = mean (deneme{kk}{:,s});
             stdres(kk,s) = std(deneme{kk}{:,s});
             end
        end
        for bb = min(veri.Class):max(veri.Class)
            for q = 4:14
             uscalc(bb,q) = (predictioncolumn(q) - meanres(bb,q)) ^2 / (2* (stdres(bb,q)^2));
            end
        end
        for mm = min(veri.Class):max(veri.Class)
            for d = 4:14
             meancalc(mm,d) =  1/(sqrt(2*pi)* stdres(mm,d)) * (2.71^(uscalc(mm,d)));
             bolumler{mm,:} = sum(veri.Class==mm)/ length(veri.Class);  
            end
        end

classcarpimlari = meancalc(:,4:14);

multiplycolumns = prod(classcarpimlari,2); end

       for nn = min(veri.Class):max(veri.Class);
            likelihood(nn) = multiplycolumns(nn) * bolumler{nn};
       end
       for gg = min(veri.Class):max(veri.Class);
               probability(gg) = likelihood(gg) / sum(likelihood);     
       end

I am trying to apply Naive Bayes Probability Density Function on my data set for my graduation project. And my advisor wanted me to do it by hand. If I set my intervals as 29 at the forth row of my code, it works and calculate the probability of my values belonging to any class. But if I change that as 28 or lower than that, it can not calculate it. Why is that?