import java.util.HashMap;
 
class Problem {
    private int count;
    private final HashMap<String, Integer> counts;
 
    public Problem() {
        this.counts = new HashMap<>();
    }
 
    public void addName(String name) {
	    counts.put(name, counts.getOrDefault(name, 0) + 1);
	    count++;
	}
 
    public double nameProportion(String name) {
        return counts.get(name) / (double) count;
    }
 
    public static void main(String[] args) {
        Problem namesCount = new Problem();
 
        namesCount.addName("James");
        namesCount.addName("John");
        namesCount.addName("Mary");
        namesCount.addName("Mary");
 
        System.out.println("Fraction of Johns: " + namesCount.nameProportion("John"));
        System.out.println("Fraction of Marys: " + namesCount.nameProportion("Mary"));
    }
}