type vector=array[1..100] of 0..1;
var  f,g:text;
     a,b,c,m,n,p,lv,i,j:longint;
     x:vector;
     v:array[1..100] of longint;
function prime(c:longint):boolean;
    begin
        if c mod 5=0 then prime:=true
          else prime:=false;
       end;
procedure adauga(var x:vector);
          begin
            if x[lv]=0 then x[lv]:=1
                 else
                    begin
                      x[lv]:=0;
                      j:=lv-1;
                      while x[j]=1 do
                          begin
                            x[j]:=0;
                            dec(j);
                          end;
                       x[j]:=1;
                    end;
          end;

function ver(c:longint):longint;
     var w,q,pp:longint;
        ok:boolean;
    begin
      w:=0;
      for j:=1 to lv do
         begin
           w:=w+c div v[j];
         end;
      {fillchar(x,lv,0);
      ok:=true;
      while ok do
         begin
           adauga(x);
           q:=0;
           pp:=1;
           for j:=1 to lv do if x[j]=1 then begin inc(q); pp:=pp*v[j] div j; end;
           if q mod 2=0 then w:=w+c div pp
                       else w:=w-(c div pp);
            if q=lv then ok:=false;
         end;      }
         ver:=w;
      end;
function cauta(a,b:longint): longint;
      var t:longint;
      begin

        if a=b then t:=a
           else
            begin
              c:=(a+b) div 2;
              m:=ver(c);
              if (m=p) and (prime(c))
                 then t:=c else
              if m>=p then t:=cauta(a,c)
                           else  t:=cauta(c+1,b);            end;
       cauta:=t;
      end;
begin
assign(f,'fact.in');
reset(f);readln(f,p);
close(f);

lv:=7;
v[1]:=5;
for i:=2 to 7 do v[i]:=v[i-1]*5;
assign(g,'fact.out');
rewrite(g);
if p=0 then writeln(g,'1') else writeln(g,cauta(0,100));
close(g);
end.