/**
 *    author:  tourist
 *    created: 01.02.2020 12:34:53       
**/
#undef _GLIBCXX_DEBUG

#include <bits/stdc++.h>

using namespace std;

mt19937 rng(5889);

template <typename A, typename B>
string to_string(pair<A, B> p);

template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p);

template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p);

string to_string(const string& s) {
  return '"' + s + '"';
}

string to_string(const char* s) {
  return to_string((string) s);
}

string to_string(bool b) {
  return (b ? "true" : "false");
}

string to_string(vector<bool> v) {
  bool first = true;
  string res = "{";
  for (int i = 0; i < static_cast<int>(v.size()); i++) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(v[i]);
  }
  res += "}";
  return res;
}

template <size_t N>
string to_string(bitset<N> v) {
  string res = "";
  for (size_t i = 0; i < N; i++) {
    res += static_cast<char>('0' + v[i]);
  }
  return res;
}

template <typename A>
string to_string(A v) {
  bool first = true;
  string res = "{";
  for (const auto &x : v) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(x);
  }
  res += "}";
  return res;
}

template <typename A, typename B>
string to_string(pair<A, B> p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}

template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " + to_string(get<2>(p)) + ")";
}

template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " + to_string(get<2>(p)) + ", " + to_string(get<3>(p)) + ")";
}

void debug_out() { cerr << endl; }

template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
  cerr << " " << to_string(H);
  debug_out(T...);
}

#ifdef LOCAL
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, m;
  cin >> n >> m;
  vector<int> limit(n);
  long long expected = 0;
  for (int i = 0; i < n; i++) {
    cin >> limit[i];
    expected += limit[i];
  }
  assert(expected % 2 == 0);
  expected /= 2;
  vector<vector<int>> c(n, vector<int>(n, 0));
  vector<vector<int>> f(n, vector<int>(n, 0));
  vector<int> total(n);
  for (int i = 0; i < m; i++) {
    int x, y, z;
    cin >> x >> y >> z;
    --x; --y;
    c[x][y] = c[y][x] = z;
    total[x] += z;
    total[y] += z;
  }
  long long sum_total = 0;
  long long sum_limit = 0;
  for (int i = 0; i < n; i++) {
    sum_total += total[i];
    sum_limit += limit[i];
  }
  bool flip = false;
  auto backup_limit = limit;
  if (sum_limit > sum_total - sum_limit) {
    expected = 0;
    for (int i = 0; i < n; i++) {
      limit[i] = total[i] - limit[i];
      expected += limit[i];
    }
    expected /= 2;
    flip = true;
  }
  vector<int> have(n, 0);
  vector<int> was(n, -1);
  int T = 0;
  vector<int> order(n);
  iota(order.begin(), order.end(), 0);
  function<int(int, int)> Dfs = [&](int v, int flow) {
    assert(flow <= limit[v] - have[v]);
    was[v] = T;
    int ret = 0;
    for (int u : order) {
      if (have[u] < limit[u] && c[v][u] > f[v][u]) {
        int take = min(limit[u] - have[u], min(c[v][u] - f[v][u], flow));
        f[v][u] += take;
        f[u][v] += take;
        have[u] += take;
        have[v] += take;
        flow -= take;
        ret += take;
        if (flow == 0) {
          return ret;
        }
      }
    }
    for (int i = 1; i < n; i++) {
      swap(order[i], order[rng() % (i + 1)]);
    }
    for (int u : order) {
      if (c[v][u] > f[v][u]) {
        for (int w : order) {
          if (was[w] != T && f[u][w] > 0) {
            flow = min(flow, limit[v] - have[v]);
            int take = min(flow, min(c[v][u] - f[v][u], f[u][w]));
            f[v][u] += take;
            f[u][v] += take;
            f[u][w] -= take;
            f[w][u] -= take;
            have[v] += take;
            have[w] -= take;
            int rt = Dfs(w, take);
            int take_back = min(take - rt, min(limit[w] - have[w], min(f[u][v], c[u][w] - f[u][w])));
            f[v][u] -= take_back;
            f[u][v] -= take_back;
            f[u][w] += take_back;
            f[w][u] += take_back;
            have[v] -= take_back;
            have[w] += take_back;
            flow -= rt;
            flow = min(flow, limit[v] - have[v]);
            ret += rt;
            if (flow == 0) {
              return ret;
            }
          }
        }
      }
    }
    return ret;
  };
  long long found = 0;
  bool last_zero = false;
  for (int iter = 0; ; iter++) {
    if (found == expected) {
      break;
    }
    shuffle(order.begin(), order.end(), rng);
    long long delta = 0;
    for (int i : order) {
      if (have[i] < limit[i]) {
        ++T;
        int rt = Dfs(i, !last_zero ? limit[i] - have[i] : (limit[i] - have[i] + 1) / 2);
        found += rt;
        delta += rt;
        if (found == expected) {
          break;
        }
      }
    }
    last_zero = (delta == 0);
//    debug(have, f);
  }
  vector<tuple<int, int, int>> res;
  vector<int> got(n);
  for (int i = 0; i < n; i++) {
    for (int j = i + 1; j < n; j++) {
      if (flip) {
        f[i][j] = c[i][j] - f[i][j];
      }
      if (i < j && f[i][j] > 0) {
        assert(f[i][j] <= c[i][j]);
        res.emplace_back(i, j, f[i][j]);
        got[i] += f[i][j];
        got[j] += f[i][j];
      }
    }
  }
  assert(got == backup_limit);
  cout << res.size() << '\n';
  for (auto& p : res) {
    cout << get<0>(p) + 1 << " " << get<1>(p) + 1 << " " << get<2>(p) << '\n';
  }
  cerr << "time = " << clock() << " ms" << '\n';
  return 0;
}