#include <iostream>
#include <algorithm>
#include <vector>
#include <sstream>

class report {
  std::vector<int> levels;
public:
  bool safe();
  friend std::istream& operator>>(std::istream& stream, report& r);
  friend std::ostream& operator<<(std::ostream& stream, report& r);
};

std::istream& operator>>(std::istream& stream, report& r) {
  r.levels.clear();
  std::string s;
  std::getline(stream, s, '\n');
  std::stringstream ss(s);
  int level;
  while (ss >> level) {
    r.levels.emplace_back(level);
  }
  return stream;
}

std::ostream& operator<<(std::ostream& stream, report& r) {
  stream << "report{";
  for (auto elem : r.levels) {
    stream << elem << ",";
  }
  stream << "}";
  return stream;
}

bool report::safe() {
  return std::adjacent_find(levels.begin(), levels.end(), [](int a, int b) {
      return a - b < 1 || a - b > 3;
    }) == levels.end()
  || std::adjacent_find(levels.begin(), levels.end(), [](int a, int b) {
      return b - a < 1 || b - a > 3;
    }) == levels.end();
}

int main() {
  report r;
  int count = 0;
  while (std::cin >> r) {
    if (r.safe()) {
      count++;
    }
  }
  std::cout << count << std::endl;
  return EXIT_SUCCESS;
}