#include<fstream>
using namespace std;
long long n, i, j, x, y, a[500003], L, p[500003], ok;
ifstream in("reguli.in");
ofstream out("reguli.out");
int main(){
    in>>n;
    in>>y;
    for(i=2; i<=n; i++){
        x=y;
        in>>y;
        a[i-1]=y-x;
    }
    for(i=2; i<n; i++){
        while(L!=0 && a[i]!=a[L+1])
            L=p[L];
        if(a[i]==a[L+1])
            L++;
        p[i]=L;
    }
    x=n-1-p[n-1];
    out<<x<<"\n";
    for(i=1; i<=x; i++)
        out<<a[i]<<"\n";
return 0;
}