#include<stdio.h>
#define NMAX 500000
int pi[NMAX+5],dif[NMAX+5];
int main() {
    freopen("reguli.in","r",stdin);
    freopen("reguli.out","w",stdout);
    int x,last,n,i,p=0;
    scanf("%d",&n);
    scanf("%d",&last);
    for(i=2;i<=n;i++) {
        scanf("%d",&x);
        dif[i-1]=x-last;
        last=x;
        }
    p=0;
    for(i=2;i<n;i++) {
        while(p && dif[i]!=dif[p+1])
            p=pi[p];
        if(dif[p+1]==dif[i])
            p++;
        pi[i]=p;
        }
    printf("%d\n",n-1-pi[n-1]);
    for(i=1;i<=n-1-pi[n-1];i++)
        printf("%d\n",dif[i]);
    return 0;
}