import java.text.DecimalFormat;
import java.util.Scanner;

public class HihoCoder1522 {
	
	static int TP =0;
	static int FP =0;
	static int FN =0;
	static int TN =0;
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		int num = in.nextInt();
		for(int i=1;i<=num;i++){
			String n = in.next();
			String m = in.next();
			if(n.equals("+") && m.equals("+")){
				TP++;
				continue;
			}
			if(n.equals("+") && m.equals("-")){
				FP++;
				continue;
			}
			if(n.equals("-") && m.equals("-")){
				TN++;
				continue;
			}
			if(n.equals("-") && m.equals("+")){
				FN++;
				continue;
			}
		}
		handle();
	}
	private static void handle() {
		DecimalFormat df =new DecimalFormat("#.00"); 
		double M = 2.00*TP + FP + FN;
		double N = TP*10.0*10.0 ;
		
		double M1 = Double.valueOf(df.format(M));
		double N1 = Double.valueOf(df.format(N));
		double score= 2 * N1/M1 ;
		System.out.println(score+"%");
	}

}