Image formed by multiple lenses

Between an object and a screen are two lenses as shown below.

The object is located $18\ \text{cm}$18, space, start text, c, m, end text from the first lens of focal length $f_1=+15\ \text{cm}$f, start subscript, 1, end subscript, equals, plus, 15, space, start text, c, m, end text. The second lens is located $15\ \text{cm}$15, space, start text, c, m, end text from the screen and has a focal length $f_2=+20\ \text{cm}$f, start subscript, 2, end subscript, equals, plus, 20, space, start text, c, m, end text.

$d=$d, equals $\text{cm}$start text, c, m, end text