program dasdas;
var n,b:real;
    i,j:longint;
    a:array[1..12] of real;
begin
readln(n);
for i:=1 to 12 do
 read(a[i]);
for i:=1 to 11 do
for j:=i+1 to 12 do
if a[i]<a[j] then begin b:=a[i]; a[i]:=a[j];a[j]:=b; end;
writeln(n*a[1]:0:2);
end.
/**************************************************************
	Problem: 2031
	User: admin
	Language: Pascal
	Result: Wrong Answer
****************************************************************/