program p1;
var f,g:text;
    st,dr,i,n,p,nrz,nz,s,rez,m:longint;
begin
    writeln('marta');
    assign(f,'fact.in');
    reset(f);
    assign(g,'fact.out');rewrite(g);
    read(f,p);
    st:=1;
    dr:=10000000;
    if p>0 then begin
        while dr>=st do
        begin
            m:=(st+dr) div 2;
            i:=1;
            nrz:=0;
            while i*5<=m do
            begin
            nrz:=nrz+1;
            s:=i;
            while s mod 5=0 do
                begin
                    nrz:=nrz+1;
                    s:=s div 5;
                end;
             i:=i+1;
             end;
            if nrz=p then begin rez:=5*(i-1); break;end
                else if p<nrz then dr:=m-1
                              else st:=m+1;
        end;
        if (dr<st) then writeln(g,'-1')
                        else writeln(g,rez);
        end
    else writeln(g,'-1');
    close(f);
    close(g);
end.