#include <stdio.h>
using namespace std;

#define Nmax 500005

long long int n, pi[Nmax], sir[Nmax], length;

void prefix(){
    int k = 0;
    for(int i = 2; i < n; ++i){
        while(sir[i] != sir[k+1] && k > 0) k = pi[k];
        if(sir[i] == sir[k+1]) ++k;
        pi[i] = k;
    }
}

void read(){
    scanf("%i", &n);
    int x1, x2;
    scanf("%i", &x1);
    for(int i = 1; i < n; ++i){
        scanf("%i", &x2);
        sir[i] = x2 - x1;
        x1 = x2;
    }
    fclose(stdin);
}

void solve(){
    prefix();
    length = (n-1) - pi[n-1];
}

void write(){
    printf("%i\n", length);
    for(int i = 1; i <= length; ++i) printf("%i\n", sir[i]);
    fclose(stdout);
}

int main(){
    freopen("reguli.in", "r", stdin);
    freopen("reguli.out", "w", stdout);

    read();
    solve();
    write();

    return 0;
}