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

unordered_map<icoord, int> m;
const int smax = 70;

void rec(icoord c, int score) {
	if (!m.contains(c)) {
		return;
	}

	int &s = m[c];
	if (s != -1 && s <= score) {
		return;
	}

	s = score;
	score++;

	rec(c + icoord(1, 0), score);
	rec(c + icoord(-1, 0), score);
	rec(c + icoord(0, 1), score);
	rec(c + icoord(0, -1), score);
}

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

	string line;
	bool inits[smax + 1][smax + 1] = {};
	int i = 0;
	while (getline(cin, line) && !line.empty()) {
		// NOTE: found part 2 is just binary search on this number until you
		// stop getting -1 as output
		if (++i > 1024) {
			break;
		}
		istringstream l(line);
		int x, y;
		l >> x;
		l.ignore();
		l >> y;
		inits[x][y] = true;
	}

	for (int x = 0; x <= smax; x++) {
		for (int y = 0; y <= smax; y++) {
			if (!inits[x][y]) {
				m[{x, y}] = -1;
			}
		}
	}

	rec({0, 0}, 0);
	cout << m[{smax, smax}] << '\n';
}