long a,b,s,t;main(){for(scanf("%ld",&b);~b&1?b/=2,++t:b%5<1?b/=5,++s:0;);a?a=!printf("%d",a%b?-1:s<t?5:a%10*(s-t?1<<(s-t)%4+4:1)%10):main(a^=b^=a^=b,s^=t^=s^=t);}