===== PascalABC.NET =====
begin
var a, b, c, d: real;
Read(a, b, c, d);
Println(Sqr(Min(Min(a, b), Min(c, d))))
end.
===== PascalABC.NET =====
begin
var a, b, c, d: real;
Read(a, b, c, d);
Println(Sqr(Min(Min(a, b), Min(c, d))))
end.