SmallR is an archer. SmallR is taking a match of archer with Zanoes. They try to shoot in the target in turns, and SmallR shoots first. The probability of shooting the target each time is <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/a7487d7e62f90136b78ae3fbf0a008396f146e13.png" style="max-width: 100.0%;max-height: 100.0%;"/> for SmallR while <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/c443c7703e51f03d0eece0b96b9e84e425878209.png" style="max-width: 100.0%;max-height: 100.0%;"/> for Zanoes. The one who shoots in the target first should be the winner.

Output the probability that SmallR will win the match.
A single line contains four integers <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/488158367221f441ba94b9475c03436069df2a7e.png" style="max-width: 100.0%;max-height: 100.0%;"/>.
def get_f_win_chance(f_num, f_denom, s_num, s_denom):
    f_hit_ch = f_num / f_denom
    s_hit_ch = s_num / s_denom
    f_win_ch = 0
    prob_remainder = 1
    while prob_remainder > 10 ** (-8):
        f_this_hit_win_ch = f_hit_ch * prob_remainder
        prob_remainder -= f_this_hit_win_ch
        f_win_ch += f_this_hit_win_ch

        s_this_hit_win_ch = s_hit_ch * prob_remainder
        prob_remainder -= s_this_hit_win_ch
    return f_win_ch


if __name__ == '__main__':
    f_num, f_denom, s_num, s_denom = (int(x) for x in input().split())
    print(get_f_win_chance(f_num, f_denom, s_num, s_denom))
