var i, n: integer; p: real;begin p:=1; readln(n); if n>2 then for i:=2 to n do p:=p*(1-1/sqr(i)) writeln(p);end.var a, b, c, d: integer;begin read(a, b, c, d); if (a>=b) or (b>=c) or (c>=d) then begin a:=sqr(a); b:=sqr(b); c:=sqr(c); d:=sqr(d); end; writeln('A=', a, ' B=', b, ' C=', c, ' D=', d)end.