uses crt,dos;
var f,g:text;
    p,n,nr:int64;
    h,m,s,s100:word;
function nr5(i:int64):int64;
 begin
 if i mod 5=0 then nr5:=nr5(i div 5)+1
     else nr5:=0;
 end;
procedure fact(var nr,n:int64);
var i:int64;
 begin
 i:=0;nr:=0;
 repeat
 inc(i,5);
 nr:=nr+nr5(i);
 until nr>=p;
 if nr=p then n:=i
    else n:=-1;
 end;
begin
clrscr;
gettime(h,m,s,s100);
writeln(h,':',m,':',s,':',s100);
assign(f,'fact.in');
reset(f);
read(f,p);
close(f);nr:=0;n:=0;
fact(nr,n);
assign(g,'fact.out');
rewrite(g);
if p<>0 then writeln(g,n) else writeln(g,1);
close(g);
gettime(h,m,s,s100);
writeln(h,':',m,':',s,':',s100);
end.