u,d,w = input().split('\n')
ul,ur = list(map(int,u.split('\n')))
d,w = int(d),int(w)
result = 0
while d:
    result += d
    m = d/(ur+w)
    d -= (ur+ul)*m
    if d:
        result += d
        m = d/(ur+w)
        d -= (ur+ul)*m
    else:
        break
print(result)