#include<bits/stdc++.h> /*   #include <ext/pb_ds/assoc_container.hpp> // Common file   #include <ext/pb_ds/tree_policy.hpp> // Including */   using namespace std;   //using namespace __gnu_pbds;      //typedefs      typedef long long ll;   typedef vector<int> vi;   typedef vector<ll> vl;   typedef vector<vi> vvi;   typedef vector<vl> vvl;   typedef pair<int,int> pii;   typedef pair<double, double> pdd;   typedef pair<ll, ll> pll;   typedef vector<pii> vii;   typedef vector<pll> vll;   typedef vector<int>::iterator vit;   typedef set<int>::iterator sit;      /*   template<typename T>   using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;   template<typename F, typename S>   using ordered_map = tree<F, S, less<F>, rb_tree_tag, tree_order_statistics_node_update>;   */      //#Defines   #define rep(i,a,b) for(i=a;i<=b;i++)   #define repR(i,a,b) for(i=a;i>=b;i--)   //#define pb push_back   #define pb emplace_back   #define F first   #define S second   #define mp make_pair   #define all(c)  c.begin(),c.end()   #define endl   n    #define pf printf   #define sf scanf   //#define left __left   //#define right __right   //#define tree __tree   #define MOD 1000000007   //#define harmonic(n) 0.57721566490153286l+log(n)      #define RESET(a,b) memset(a,b,sizeof(a))   #define gcd(a,b) __gcd(a,b)   #define lcm(a,b) (a*(b/gcd(a,b)))   #define sqr(a) ((a) * (a))      #define optimize() ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);   #define fraction() cout.unsetf(ios::floatfield); cout.precision(10); cout.setf(ios::fixed,ios::floatfield);      const double PI = acos(-1);   const double eps = 1e-9;   const int inf = 2000000000;   const ll infLL = 9000000000000000000;         //Bit Operations   inline bool checkBit(ll n, int i) { return n&(1LL<<i); }   inline ll setBit(ll n, int i) { return n|(1LL<<i);; }   inline ll resetBit(ll n, int i) { return n&(~(1LL<<i)); }      int fx[] = {0, 0, +1, -1};   int fy[] = {+1, -1, 0, 0};   //int dx[] = {+1, 0, -1, 0, +1, +1, -1, -1};   //int dy[] = {0, +1, 0, -1, +1, -1, +1, -1};         //Inline functions      inline bool EQ(double a, double b) { return fabs(a-b) < 1e-9; }   inline bool isLeapYear(ll year) { return (year%400==0) || (year%4==0 && year%100!=0); }   inline void normal(ll &a) { a %= MOD; (a < 0) && (a += MOD); }   inline ll modMul(ll a, ll b) { a %= MOD, b %= MOD; normal(a), normal(b); return (a*b)%MOD; }   inline ll modAdd(ll a, ll b) { a %= MOD, b %= MOD; normal(a), normal(b); return (a+b)%MOD; }   inline ll modSub(ll a, ll b) { a %= MOD, b %= MOD; normal(a), normal(b); a -= b; normal(a); return a; }   inline ll modPow(ll b, ll p) { ll r = 1; while(p) { if(p&1) r = modMul(r, b); b = modMul(b, b); p >>= 1; } return r; }   inline ll modInverse(ll a) { return modPow(a, MOD-2); }   inline ll modDiv(ll a, ll b) { return modMul(a, modInverse(b)); }   inline bool isInside(pii p,ll n,ll m) { return (p.first>=0&&p.first<n&&p.second>=0&&p.second<m); }   inline bool isInside(pii p,ll n)  { return (p.first>=0&&p.first<n&&p.second>=0&&p.second<n); }   inline bool isSquare(ll x)     { ll s = sqrt(x); return (s*s==x); }   inline bool isFib(ll x)     { return isSquare(5*x*x+4)|| isSquare(5*x*x-4); }   inline bool isPowerOfTwo(ll x)   { return ((1LL<<(ll)log2(x))==x); }         struct func   {    //this is a sample overloading function for sorting stl    bool operator()(pii const &a, pii const &b)     {     if(a.F==b.F)      return (a.S<b.S);     return (a.F<b.F);    }   };      //Prime Number Generator      /*   #define M 100000000   int marked[M/64 + 2];      #define on(x) (marked[x/64] & (1<<((x%64)/2)))   #define mark(x)  marked[x/64] |= (1<<((x%64)/2))      vl prime;      bool isPrime(int num) {     return num > 1 && (num == 2 || ((num & 1) && !on(num)));    }      void sieve(ll n) {    for (ll i = 3; i * i < n; i += 2) {     if (!on(i)) {      for (ll j = i * i; j <= n; j += i + i) {       mark(j);      }     }    }    prime.pb(2);    for(ll i = 3; i <= n; i += 2) {     if(!on(i)) prime.pb(i);     }   }      */      //   //debug   #ifdef tajir   template < typename F, typename S >   ostream& operator << ( ostream& os, const pair< F, S > & p ) {    return os <<  (  << p.first <<  ,   << p.second <<  ) ;   }      template < typename T >   ostream &operator << ( ostream & os, const vector< T > &v ) {    os <<  { ;    for(auto it = v.begin(); it != v.end(); ++it) {     if( it != v.begin() ) os <<  ,  ;      os << *it;    }    return os <<  } ;   }      template < typename T >   ostream &operator << ( ostream & os, const set< T > &v ) {    os <<  [ ;    for(auto it = v.begin(); it != v.end(); ++it) {     if( it != v.begin() ) os <<  ,  ;      os << *it;    }    return os <<  ] ;   }      template < typename T >   ostream &operator << ( ostream & os, const multiset< T > &v ) {    os <<  [ ;    for(auto it = v.begin(); it != v.end(); ++it) {     if( it != v.begin() ) os <<  ,  ;     os << *it;    }    return os <<  ] ;   }      template < typename F, typename S >   ostream &operator << ( ostream & os, const map< F, S > &v ) {    os <<  [ ;    for(auto it = v.begin(); it != v.end(); ++it) {     if( it != v.begin() ) os <<  ,  ;     os << it -> first <<   =   << it -> second ;     }    return os <<  ] ;   }      #define dbg(args...) do {cerr << #args <<   :  ; faltu(args); } while(0)      clock_t tStart = clock();   #define timeStamp dbg( Execution Time:  , (double)(clock() - tStart)/CLOCKS_PER_SEC)      void faltu () {    cerr << endl;   }      template <typename T>   void faltu( T a[], int n ) {    for(int i = 0; i < n; ++i) cerr << a[i] <<    ;    cerr << endl;   }      template <typename T, typename ... hello>   void faltu( T arg, const hello &... rest) {    cerr << arg <<    ;    faltu(rest...);   }   #else   #define dbg(args...)   #endif // tajir      int main()   {    #ifdef tajir     freopen( input.txt ,  r , stdin);    #else     // online submission    #endif    optimize();        int n;    int a[10001];    int x[10001];       cin >> n;       a[0] = 0;       for(int i = 1; i <= n; ++i)     cin >> a[i];       for(int i = n; i > 0; --i) {     x[i-1] = a[i] - a[i-1];    }    dbg(x,n);       vi res;       for(int i = 1; i <= n; ++i) {     vi v(i,-inf);     dbg(i);     bool flag = true;     for(int j = 0; j < n; ++j) {      if(v[j%i] == -inf)       v[j%i] = x[j];      else {       if(v[j%i] == x[j]) continue;       else {        dbg(j%i,v[j%i],x[j]);        flag = false;        break;       }      }      dbg(v);     }     dbg(flag);     if(flag)      res.pb(i);    }       cout << res.size() << endl;       for(auto x : res)      cout << x <<    ;    cout << endl;        return 0;   }                     //?