#include <fstream.h>
int main ()
{ long v[1000],n,i,j,s,x,p,aux,y,ok2,ok3;
int ok;
ifstream f ("economie.in");
ofstream g ("economie.out");
f>>n;
for (i=1; i<=n; i++) {
    f>>v[i]; }
do { ok=1;
     for (i=1;i<=n-1;i++){
	    if (v[i]>v[i+1]) {
		    aux=v[i];
		    v[i]=v[i+1];
		    v[i+1]=aux;
		    ok=0; }}
    } while (ok==0);
ok=0; s=0; i=1;
 while (ok==0 && i<=n) {
		 s=s+v[i]; j=i+1;  y=0;  ok3=1;
		 while (ok3==1 && j<=n) {
			      if (v[j]-s==0) {j++;y++;}
			      else { p=v[j]-s; x=1; ok2=0;
				     while (ok2==0 && x<=i) {
					     if (p%v[x]==0) { ok2=1; y++; j++;}
					     else x++; }}
			                     
		              if (y==0) ok3=0; }
		 if (j-i-1==y && y!=0) ok=1;
		 else i++; } 
 g<<i<<endl;
for (j=1;j<=i;j++){
	  g<<v[j]<<endl; }
f.close ();
g.close ();
return 0;
}