#include <cstdio>

using namespace std;

long long v[500010],rez[500010];

int main()
{
    freopen("reguli.in","r",stdin);
    freopen("reguli.out","w",stdout);
    int n,l=0,sol,a;
    scanf("%d",&n);
    for(int i=0;i<n;i++)
        scanf("%d",&v[i]);
    l++;rez[l]=v[1]-v[0];
    sol=1;
    a=1;
    for(int i=2;i<n;i++)
    {
        if(v[i]-v[i-1]==rez[a])
        {
            a++;
            if(a==sol+1) a=1;
            l++;
            rez[l]=v[i]-v[i-1];
        }
        else if(v[i]-v[i-1]==rez[1])
        {
            a=2;
            sol=l;
            l++;
            rez[l]=v[i]-v[i-1];
        }
        else
        {
            l++;
            rez[l]=v[i]-v[i-1];
            sol=l;
            a=1;
        }
    }
    printf("%d\n",sol);
    for(int i=1;i<=sol;i++)
        printf("%d\n",rez[i]);
    return 0;
}