def indices(lst, item):
    return [i for i, x in enumerate(lst) if x == item]
 
temp_list=[]
for x in data:
    temp_list.append(x[0])
 
print(len(temp_list))
 
 
for i in range(0,len(temp_list)):
    temp=indices(temp_list,temp_list[i])
    if len(temp)>=2:
        cc=65
        for k in temp:
            ad=chr(cc)
            temp_list[k]=temp_list[k]+'-'+ad
            cc+=1
 
 
for j in range(0,len(data)):
    data[j][0]=temp_list[j]
 
print(data)