#include "validation.h"
using namespace std;

typedef long long ll;
typedef long double ld;
typedef pair<ll, ll> ii;
typedef vector<ll> vi;
typedef vector<vi> vvi;
typedef vector<vvi> vvvi;
typedef vector<vvvi> vvvvi;
typedef vector<ii> vii;

#define x first
#define y second
#define pb push_back
#define eb emplace_back
#define all(v) (v).begin(), (v).end()

// Checks that the output is "impossible" if and only if this is the answer,
// checks whether the reported maximal distance matches the answer, and finally
// whether the reported optimal position has (at most) this maximal distance.

vvi A;
ll h, w;
vvvi D;

ll dfs(ll i, ll j, ll t) {
	if (D[j][i][t] != -2) return D[j][i][t];
	D[j][i][t] = -1;
	if (A[j][i] == t) return D[j][i][t] = 0;

	ll bi, bj, ba = -100000000;
	for (ii p : vii{ii{i+1, j}, ii{i, j+1}, ii{i-1, j}, ii{i, j-1}}) {
		if (p.x >= 0 && p.x < w && p.y >= 0 && p.y < h) {
			ll a = A[p.y][p.x];
			if (abs(a - t) < abs(ba - t) || (abs(a - t) == abs(ba - t) &&
					abs(a - A[j][i]) < abs(ba - A[j][i]))) {
				ba = a;
				bi = p.x;
				bj = p.y;
			}
		}
	}
	ll r = dfs(bi, bj, t)+1;
	if (r == 0) r = -1;
	D[j][i][t] = r;
	return r;
}

int main(int argc, char **argv) {
    // Set up the input and answer streams.
    std::ifstream in(argv[1]);
    std::ifstream ans(argv[2]); // Only for custom checker.
    OutputValidator v(argc, argv);

	string s;
	ans >> s;
	if (s == "impossible") {
		v.test_string("impossible");
		v.newline();
		return 0;
	}

	in >> h >> w;
	ll a, r;
	ll ra;
	a = v.read_integer("a", 1, h*w);
	v.space();
	r = v.read_integer("r", 2, h*w);
	v.newline();
	ans >> ra;
	v.check(r == ra, "Reported distance is not correct.");

	ll x, y;
	A = vvi(h, vi(w, 0));
	D = vvvi(h, vvi(w, vi(h*w+1, -2)));
	for (ll j = 0; j < h; j++) {
		for (ll i = 0; i < w; i++) {
			in >> A[j][i];
			if (A[j][i] == a) {
				x = i; y = j;
			}
		}
	}

	for (ll t = 1; t <= h*w; t++) {
		ll rt = dfs(x, y, t);
		v.check(rt >= 0 && rt <= r, "Reported distance does not equal actual distance.");
	}
}