var f,g:text;
        p,a,b,i,nr,y,nr1,x,z,t:longint;
begin
assign(f,'fact.in');reset(f);
assign(g,'fact.out');rewrite(g);
read(f,p);
a:=p;
b:=p;
for i:= 1 to maxlongint do begin
        if p=0 then begin
                        write(g,1);
                        break;
                        end;
        if i mod 2=0 then begin
                        x:=i;
                        z:=x;
                        repeat
                        if z mod 2<>0 then break;
                        x:=x div 2;
                        nr:=nr+1;
                        z:=x;
                        until x=1;
                        end;
        if (nr>=a)and(nr1>=b) then begin
                                        write(g,i);
                                        break;
                                        end;
        if i mod 5=0 then begin
                        y:=i;
                        t:=y;
                        repeat
                        if t mod 5<>0 then break;
                        y:=y div 5;
                        nr1:=nr1+1;
                        t:=y;
                        until y=1;
                        end;
        if (nr>=a)and(nr1>=b) then begin
                                        write(g,i);
                                        break;
                                        end;
        end;
close(f);
close(g);
end.