a[10001]={0,1},b[10001],n,i,j,k,s=1;main(x){for(scanf("%d",&n);!a[n]&&s;x++){memcpy(b,a,n*4+4);for(s=i=0;i++<n;j=0)if(a[i]){for(k=i;k;k&=k-1)j++;i+j>n|a[i+j]||b[i+j]++|s++;i<j|a[i-j]||b[i-j]++|s++;}memcpy(a,b,n*4+4);}i=!printf("%d",a[n]?x:-1);}