#include<bits/stdc++.h>   using namespace std;   typedef double db;   typedef uint32_t u32;   typedef uint64_t u64;   typedef pair<int, int> pii;   typedef pair<int, int> point;   #define fi first   #define se second   #define pb(x) push_back(x)   #define SZ(x) ((int) (x).size())   #define all(x) (x).begin(), (x).end()   #define rep(i, l, r) for(int i = l; i < r; i++)   typedef long long ll;   const int mod = 998244353;            int main() {   #ifdef local    freopen( in.txt ,  r , stdin);   #endif    ios::sync_with_stdio(false);    cin.tie(0), cout.tie(0);    const int mod = 1e9 + 7;    int n;    cin >> n;    vector<int> a(n);    ll tot = 0;    for(auto &e : a) {     cin >> e;     tot += e;    }    if(tot % n) {     cout <<  0 n ;     return 0;    }    vector<int> fac(n + 1, 1);    vector<int> ifac(n + 1, 1);    for(int i = 2; i <= n; i++) {     fac[i] = (ll) fac[i - 1] * i % mod;     ifac[i] = (ll) ifac[mod % i] * (mod - mod / i) % mod;    }    for(int i = 2; i <= n; i++) {     ifac[i] = (ll) ifac[i] * ifac[i - 1] % mod;    }    auto C = [&](int n, int m) {     if(n < m || m < 0) return 0ll;     return (ll) fac[n] * ifac[m] % mod * ifac[n - m] % mod;    };    ll avg = tot / n;    vector<int> l, r;    int eq = 0;    for(auto &e : a) {     if(e > avg) {      r.push_back(e);     } else if(e < avg) {      l.push_back(e);     } else {      eq++;     }    }    int ans = 1;    if(l.size() > 1 && r.size() > 1) {     ans = 2;    }    if(l.size() == 1) {     r.push_back(l[0]);     l.clear();    }    if(r.size() == 1) {     l.push_back(r[0]);     r.clear();    }    sort(all(l));    sort(all(r));    int a1 = fac[l.size()];    int a2 = fac[r.size()];    for(int i = 0, j = 0; i < (int) l.size(); i = j) {     while(j < (int) l.size() && l[j] == l[i]) {      j++;     }     a1 = (ll) a1 * ifac[j - i] % mod;    }    for(int i = 0, j = 0; i < (int) r.size(); i = j) {     while(j < (int) r.size() && r[j] == r[i]) {      j++;     }     a2 = (ll) a2 * ifac[j - i] % mod;    }    int a3 = C(n, eq);    ans = (ll) ans * a1 % mod;    ans = (ll) ans * a2 % mod;    ans = (ll) ans * a3 % mod;    cout << ans <<   n ;    return 0;   }   