var a,i,j,k:longint;
begin
readln(a);
for i:=2 to trunc(sqrt(a)) do
begin
if a mod i=0 then
begin
j:=0;
break;
end else
j:=1;
end;
if j:=1 then write('Yes') else write('No');
end.

var

var i,a:real;
begin  read(a);