The city of Cary is holding a special census. The city has collected data on cards that each hold the voting district and age of a citizen. The districts are numbered 1 through 22, and residents' ages range from 0 through 105. Design a program that allows a clerk to go through the cards, entering the district for each citizen until an appropriate sentinel value is entered. The output is a list of all 22 districts and the number of residents in each.