file = open("input.txt")
vei = [(0,0)]
steg = [0,0]
for line in file:
    for i in range(len(line)-1):
        if(not line[i].isalpha()):
            x = int(line[i])
            if(line[i+1] == "H"):
                steg[0] = steg[0] + x
            if(line[i+1] == "V"):
                steg[0] = steg[0] - x
            if(line[i+1] == "F"):
                steg[1] = steg[1] + x
            if(line[i+1] == "B"):
                steg[1] = steg[1] - x
            #print(steg)
            vei.append((steg[0], steg[1]))

sortert_x = sorted(vei, key=lambda tup: tup[0])
sortert_y = sorted(vei, key=lambda tup: tup[1])
diffx = sortert_x[-1][0] - sortert_x[0][0]
diffy = sortert_y[-1][1] - sortert_y[0][1]
area = diffx*diffy
visited = len(set(vei))
not_visited = area - visited
print(visited/not_visited)