#include #define REP(i, n) for (int i = 0; (i) < (int)(n); ++ (i)) #define REP3(i, m, n) for (int i = (m); (i) < (int)(n); ++ (i)) #define REP_R(i, n) for (int i = (int)(n) - 1; (i) >= 0; -- (i)) #define REP3R(i, m, n) for (int i = (int)(n) - 1; (i) >= (int)(m); -- (i)) #define ALL(x) std::begin(x), std::end(x) using namespace std; /** * @note O(\sqrt{n}) */ struct prepared_primes { int size; std::vector sieve; std::vector primes; prepared_primes(int size_) : size(size_) { sieve.resize(size); REP3 (p, 2, size) if (sieve[p] == 0) { primes.push_back(p); for (int k = p; k < size; k += p) { if (sieve[k] == 0) { sieve[k] = p; } } } } std::vector list_prime_factors(int64_t n) { assert (1 <= n and n < (int64_t)size * size); std::vector result; // trial division for large part for (int p : primes) { if (n < size or n < (int64_t)p * p) { break; } while (n % p == 0) { n /= p; result.push_back(p); } } // small part if (n == 1) { // nop } else if (n < size) { while (n != 1) { result.push_back(sieve[n]); n /= sieve[n]; } } else { result.push_back(n); } assert (std::is_sorted(ALL(result))); return result; } std::vector list_all_factors(int64_t n) { auto p = list_prime_factors(n); std::vector d; d.push_back(1); for (int l = 0; l < p.size(); ) { int r = l + 1; while (r < p.size() and p[r] == p[l]) ++ r; int n = d.size(); REP (k1, r - l) { REP (k2, n) { d.push_back(d[d.size() - n] * p[l]); } } l = r; } return d; } }; int solve(int n, const vector & a) { int sum = accumulate(ALL(a), 0); prepared_primes primes(sqrt(sum) + 3); auto ds = primes.list_all_factors(sum); sort(ALL(ds)); for (int d : ds) { int acc = 0; REP (i, n) { acc += a[i]; if (acc > d) { break; } else if (acc == d) { acc = 0; } } if (acc == 0) { return sum / d; } } assert (false); } int main() { int n; cin >> n; vector a(n); REP (i, n) { cin >> a[i]; } cout << solve(n, a) << endl; return 0; }