#include <bits/stdc++.h>
using namespace std;

bool check(const auto &t) {
	int pos = (t[1] > t[0]) ? 1 : -1;
	for (int i = 0; i < t.size() - 1; i++) {
		int diff = (t[i + 1] - t[i]) * pos;
		if (diff < 1 || diff > 3) {
			return false;
		}
	}
	return true;
}

int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);

	int total = 0;
	string line;
	while (getline(cin, line) && !line.empty()) {
		istringstream l(line);
		vector<int> t;
		while (!l.eof()) {
			int x;
			l >> x;
			t.push_back(x);
		}
		if (check(t)) {
			total++;
		} else {
			for (int i = 0; i < t.size(); i++) {
				vector<int> tt;
				for (int j = 0; j < t.size(); j++) {
					if (j == i)
						continue;
					tt.push_back(t[j]);
				}
				if (check(tt)) {
					total++;
					break;
				}
			}
		}
	}
	cout << total << '\n';
}