#include<stdio.h>
#define NM 500001

int v[NM],d[NM],u[NM],n;

void prefix()
{
int i,j;
j=0;
u[1]=0;
for(i=2;i<n;i++)
	{
	while(j>0&&d[i]!=d[j+1])j=u[j];
	if(d[i]==d[j+1])j++;
	u[i]=j;
	}
}

int main()
{
freopen("reguli.in","r",stdin);
freopen("reguli.out","w",stdout);
scanf("%d",&n);
int i,j;
scanf("%d",&v[0]);
for(i=1;i<n;i++)
	{
	scanf("%d",&v[i]);
	d[i]=v[i]-v[i-1];
	}
prefix();
for(i=1;u[i]==0;i++);
printf("%d\n",i-1);
for(j=1;j<i;j++)
	printf("%d\n",d[j]);
return 0;
}