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#include <algorithm>
#include <cstdio>
#include <utility>
#include <vector>

#define COST first
#define VALUE second

using namespace std;

struct state {
  int cost0 = 0;
  vector<pair<int, int> > options;
};

int input[500001];
state states[2];

void update(int value, state& prevState, state& currState) {
  pair<int, int> tmp;
  vector<pair<int, int> > v;

  if (prevState.cost0 >= 0) {  // don't connect back
    v.push_back(make_pair(prevState.cost0, value));
  }

  for (int i = 0; i < prevState.options.size(); i++) {
    tmp = prevState.options[i];
    tmp.COST++;
    tmp.VALUE += value;
    v.push_back(tmp);
  }

  sort(v.begin(), v.end());

  currState.cost0 = -1;
  currState.options.clear();

  int bestValue = 0xf0000000;
  for (int i = 0; i < v.size(); i++) {
    if (v[i].VALUE > bestValue) {
      currState.options.push_back(v[i]);
      bestValue = v[i].VALUE;
    }
  }

  for (int i = 0; i < v.size(); i++) {
    if (currState.options[i].VALUE >= 0) {
      currState.cost0 = currState.options[i].COST;
      break;
    }
  }

  // printf("(%d) %d: c0: %d\n", prevState.cost0, value, currState.cost0);
  // for (int i = 0; i < currState.options.size(); i++) {
  //   printf("  c:%d v:%d\n", currState.options[i].COST, currState.options[i].VALUE);
  // }
}

int main() {
  int n;
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    scanf("%d", &input[i]);
  }

  for (int i = 1; i <= n; i++) {
    update(input[i], states[(i + 1) & 1], states[i & 1]);
  }

  printf("%d\n", states[n & 1].cost0);
  return 0;
}