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// O(n^3 log n)
// attempt 2
#include <bits/stdc++.h>
using std::cin, std::cout, std::vector;
using u8 = std::uint8_t;
using u16 = std::uint16_t;
using i32 = std::int32_t;
using u32 = std::uint32_t;
using u64 = std::uint64_t;
#define REP(i, n) for (u32 i=0; i<(n); ++i)
#define DEBUG(x) std::cerr << #x << " = " << x << "\n"

void init_io() {
  cin.tie(nullptr);
  std::ios::sync_with_stdio(false);
}

u32 low_bit(const u32 x) {
  return x & -x;
}

constexpr u32 bit_clear_threshold = 20;

class BIT {
public:
  BIT(const u32 n1): counts(512, 0) {}

  void clear() {
    counts.assign(512, 0);
  }

  void insert(const u32 x) {
    u32 p = x + 1;
    REP(i, 9) {
      counts[p] += 1;
      p = (p + low_bit(p)) & 511;
    }
    counts[0] = 0;
  }

  void remove(const u32 x) {
    u32 p = x + 1;
    REP(i, 9) {
      counts[p] -= 1;
      p = (p + low_bit(p)) & 511;
    }
    counts[0] = 0;
  }

  u32 count_below(const u32 x) {
    u32 p = x;
    u32 res = 0;
    REP(i, 8) {
      res += counts[p];
      p &= (p-1);
    }
    return res;
  }
private:
  u32 n;
  // counts[x] = sum([x-low_bit(x), x))
  vector<u32> counts;
};

u64 divide(const u64 a, const u64 b) {
  assert(a % b == 0);
  return a / b;
}

vector<i32> read_prefix_sums() {
  u32 n;
  cin >> n;
  vector<i32> s;
  s.reserve(n + 1);
  i32 s1 = 0;
  s.push_back(s1);
  REP(i, n) {
    i32 a;
    cin >> a;
    s1 += a;
    s.push_back(s1);
  }
  return s;
}

vector<i32> read_prefix_sums_perf() {
  std::mt19937 rng;
  std::uniform_int_distribution<i32> dist{-20000, 20000};

  u32 n = 500;
  vector<i32> s;
  s.reserve(n + 1);
  i32 s1 = 0;
  s.push_back(s1);
  REP(i, n) {
    i32 a = dist(rng);
    s1 += a;
    s.push_back(s1);
  }
  return s;
}

// Count (a, a') such that:
// s(a) = s(a')
// a < a'
// O(n log n)
u64 solve_p1(const vector<i32> &s) {
  u64 res = 0;
  std::map<i32, u32> counts;
  for (const i32 x : s) {
    u32 &c = counts[x];
    res += c;
    c += 1;
  }
  return res;
}

// Count (a, b, a', b') such that:
// mult * s(a) + s(b) = mult * s(a') + s(b')
// a < a'
// b < b'
// O(n^2 log n)
u64 solve_p2(const vector<i32> &s, const int mult) {
  const u32 n = s.size();

  struct Entry {
    u32 a;
    u32 b;
    i32 sum;
  };

  vector<Entry> entries;
  entries.reserve(n * n);
  REP(a, n) REP(b, n) {
    entries.push_back(Entry{a, b, mult * s[a] + s[b]});
  }
  std::sort(entries.begin(), entries.end(),
      [](const Entry &e1, const Entry &e2) -> bool {
        return std::tuple(e1.sum, e1.b, e1.a) < std::tuple(e2.sum, e2.b, e2.a);
      }
  );

  u64 result = 0;
  BIT set_a(n);

  auto sum_begin = entries.begin();
  while (sum_begin != entries.end()) {
    auto sum_end = sum_begin + 1;
    while (sum_end != entries.end() && sum_end->sum == sum_begin->sum) {
      ++sum_end;
    }

    auto b_begin = sum_begin;
    while (b_begin != sum_end) {
      auto b_end = b_begin + 1;
      while (b_end != sum_end && b_end->b == b_begin->b) {
        ++b_end;
      }

      for (auto it = b_begin; it != b_end; ++it) {
        result += set_a.count_below(it->a);
      }
      for (auto it = b_begin; it != b_end; ++it) {
        set_a.insert(it->a);
      }

      b_begin = b_end;
    }

    for (auto it = sum_begin; it != sum_end; ++it) {
      set_a.remove(it->a);
    }

    sum_begin = sum_end;
  }

  return result;
}

// Count (a, b, c, a', b', c') such that:
// s(a) + s(b) + s(c) = s(a') + s(b') + s(c')
// a < a'
// b < b'
// c < c'
// O(n^3 log n)
u64 solve_p3(const vector<i32> &s) {
  const u32 n = s.size();

  const i32 min_sum = 3 * *std::min_element(s.begin(), s.end());
  const i32 max_sum = 3 * *std::max_element(s.begin(), s.end());

  // max_sum - min_sum <= 3 * 500 * 20'000 = 30M
  // 120 MB
  u32 *entries_begin = new u32[max_sum - min_sum + 2]{};

  // count
  REP(c, n) {
    REP(b, c) {
      REP(a, b) {
        entries_begin[s[c] + s[b] + s[a] - min_sum] += 6;
      }
      entries_begin[2 * s[c] + s[b] - min_sum] += 3;
      entries_begin[2 * s[b] + s[c] - min_sum] += 3;
    }
    entries_begin[3 * s[c] - min_sum] += 1;
  }

  {
    u32 pos = 0;
    for (i32 sum = min_sum; sum <= max_sum; ++sum) {
      u32 &e = entries_begin[sum - min_sum];
      pos += e;
      e = pos;
    }
    entries_begin[max_sum - min_sum + 1] = pos;
    assert(pos == n * n * n);
  }

  struct Entry {
    u16 b;
    u16 c;
  };
  // 500 MB
  // vector<Entry> entries(n * n * n);
  Entry *entries = new Entry[n * n * n];

  REP(c_rev, n) {
    const u32 c = n - 1 - c_rev;
    REP(b, n) {
      REP(a, b) {
        u32 &e = entries_begin[s[c] + s[b] + s[a] - min_sum];
        entries[--e] = Entry{u16(a), u16(c)};
        entries[--e] = Entry{u16(b), u16(c)};
      }
      {
        u32 &e = entries_begin[s[c] + 2 * s[b] - min_sum];
        entries[--e] = Entry{u16(b), u16(c)};
      }
    }
  }

  u64 count_c_smaller = 0;
  u64 count_bc_smaller = 0;
  BIT set_b(n);
  
  for (i32 sum = min_sum; sum <= max_sum; ++sum) {
    const u32 sum_begin = entries_begin[sum - min_sum];
    const u32 sum_end = entries_begin[sum - min_sum + 1];
    u32 c_begin = sum_begin;
    while (c_begin != sum_end) {
      const auto c = entries[c_begin].c;
      u32 c_end = c_begin + 1;
      while (c_end != sum_end && entries[c_end].c == c) {
        ++c_end;
      }
      count_c_smaller += u64(c_end - c_begin) * u64(c_begin - sum_begin);

      for (u32 i = c_begin; i != c_end; ++i) {
        count_bc_smaller += set_b.count_below(entries[i].b);
      }
      for (u32 i = c_begin; i != c_end; ++i) {
        set_b.insert(entries[i].b);
      }

      c_begin = c_end;
    }

    if (sum_end - sum_begin >= bit_clear_threshold) {
      set_b.clear();
    } else {
      for (u32 i = sum_begin; i != sum_end; ++i) {
        set_b.remove(entries[i].b);
      }
    }
  }

  // A = #(<<<)
  // B = #(><<) = #(>><)
  // C = #(=<<)
  // D = #(=<>)
  // E = #(==<)
  // count_c_smaller = A + 3B + 2C + 2D + E
  // count_bc_smaller = A + B + C
  const u64 C = n * solve_p2(s, 1);
  const u64 D = n * solve_p2(s, -1);
  const u64 E = n * n * solve_p1(s);
  // A + 3B
  const u64 a_plus_3b = count_c_smaller - 2 * C - 2 * D - E;
  // A + B
  const u64 a_plus_b = count_bc_smaller - C;
  // solve for A
  const u64 A = divide(3 * a_plus_b - a_plus_3b, 2);

  return A;
}

// Count (a, b, c, a', b', c') such that:
// s(a) + s(b) + s(c) = s(a') + s(b') + s(c')
// a < a'
// b < b'
// c < c'
// (a, a') < (b, b') < (c, c')
u64 solve_problem(const vector<i32> &s) {
  // Without the (a, a') < (b, b') < (c, c') constraint.
  u64 res = solve_p3(s);

  // Subtract:
  // E1: (a, a') == (b, b')
  // E2: (a, a') == (c, c')
  // E3: (b, b') == (c, c')
  res -= 3 * solve_p2(s, 2);

  // Add E1 & E2, E1 & E3, E2 & E3.
  // Subtract E1 & E2 & E3.
  // They are all equivalent.
  res += 2 * solve_p1(s);

  // Divide by 3! permutations of (a, a'), (b, b'), (c, c').
  return divide(res, 6);
}

int main() {
  init_io();

  const vector<i32> s = read_prefix_sums();
  const u64 result = solve_problem(s);
  cout << result << "\n";
}