var f:text;
    p,putere,a,aux:longint;
begin
assign(f,'fact.in');
reset(f);
readln(f,p);
close(f);
if p=0 then begin assign(f,'fact.out');
                  rewrite(f);
                  writeln(f,1);
                  close(f);
                  halt;
            end;
if p=1 then begin assign(f,'fact.ou');
                  rewrite(f);
                  writeln(f,5);
                  close(f);
                  halt;
            end;
if p=2 then begin assign(f,'fact.out');
                  rewrite(f);
                  writeln(f,10);
                  close(f);
                  halt;
            end;
a:=15;
p:=p-2;
while p<>0 do
begin
     aux:=a;
     putere:=0;
     while aux mod 5=0 do
     begin inc(putere);
           aux:=aux div 5;
     end;
     p:=p-putere;
     if p=0 then begin assign(f,'fact.out');
                        rewrite(f);
                        writeln(f,a);
                        close(f);
                        halt;
                  end;
     a:=a+5;
end;
if p<0 then begin assign(f,'fact.out');
                  rewrite(f);
                  writeln(f,-1);
                  close(f);
                  halt;
             end;
end.