import sys import math p = sys.stdin.readline().strip().split() q = sys.stdin.readline().strip().split() p_set = set(p+q) p_proba = {} q_proba = {} for m in p: if(m in p_proba.keys()): p_proba[m] = p_proba[m] + 1 else: p_proba[m] = 1 for m in q: if(m in q_proba.keys()): q_proba[m] = q_proba[m] + 1 else: q_proba[m] = 1 KL = 0.0 for m in p_set: p_tmp = float(p_proba[m])/float(len(p)) q_tmp = float(q_proba[m])/float(len(q)) pdq = p_tmp/q_tmp KL = KL + p_tmp * math.log(pdq,2) print(round(KL,2))