extract first letter from worf of string

I am getting errror here while compiling this code portion inputfile = textread('wi tribe.txt','%s'); % filename2='lta vlst5.txt'; [m,n]= size(inputfile);

for j=1:m str=inputfile(j); str2=str{j,1}

    if (strcmp(str1,str))
        count1=count1+1;
    end

    %numberofsentences=count1

end at line str2 =str{ j, 1} its giving error ...index exceed dimension matrix

newbiw in matlab so unable to debug it