//#include<algorithm>
//using namespace std;
#include<stdio.h>
long long int n,a[501],b[501];
void solve(){
    long long int i,j,ok;
    scanf("%lld",&n);
    for(i=1; i<=n; ++i)
        scanf("%lld",&a[i]);
    for(i=1; i<n; b[i]=(a[i+1]-a[i]),++i);
    for(i=1,ok=1; i<n&&ok; ){
        ok=0;
		for(++i; i<n&&b[i]!=b[1]; ++i);
		for(j=i; j<2*i-1&&j<n; ++j)
            if(b[j-i+1]!=b[j])
                ok=1;
        if(!ok){
            for(printf("%lld\n",i-1),j=1; j<i; ++j)
				printf("%lld\n",b[j]);}}}
int main(){
    freopen("reguli.in","r",stdin);
    freopen("reguli.out","w",stdout);
    solve();
    return 0;}