#include <iostream>
#include <cmath>
#include <cstdio>
using namespace std;

const int NLOW = 4;
const int NHIGH = 9;
const int MLOW = 2;
const int MHIGH = 10;

const int EMPTY = 0;
const int SECTION = 1;

int grid[NHIGH+2][NHIGH+2];

int fill(int i, int j)
{
	if (grid[i][j] == EMPTY)
		return 0;
	grid[i][j] = EMPTY;
	return 1 + fill(i+1,j) + fill(i-1,j) + fill(i,j+1) + fill(i,j-1);
}

int main()
{
	int n, m, t, r, c;
	char op;

	cin >> n >> m >> t >> op;
		if (n < NLOW || n > NHIGH) {
			cout << "ERROR: invalid n " << n << endl; return 1; }
		if (m < MLOW || m > MHIGH) {
			cout << "ERROR: invalid m " << m << endl; return 2; }
		if (t < 0) {
			cout << "ERROR: invalid t" << t << endl; return 3; }
		if (op != '+' && op != '-' && op != '*' && op != '/') {
			cout << "ERROR: invalid op" << op << endl; return 4; }
		for(int i=0; i<n+2; i++)
			for(int j=0; j<n+2; j++)
				grid[i][j] = EMPTY;
		bool bad = false;;
		for(int i=0; i<m; i++) {
			cin >> r >> c;
			if (r < 1 || r > n) {
				cout << "ERROR: invalid r " << r << endl; return 5;
				bad = true;
			}
			if (c < 1 || c > n) {
				cout << "ERROR: invalid c " << c << endl; return 6;
				bad = true;
			}
			if (!bad) {
				if (grid[r][c] == SECTION) {
					cout << "ERROR: repeat square " << r << ',' << c << endl; return 7; }
				grid[r][c] = SECTION;
			}
		}
		if (!bad) {
			int nfill = fill(r, c);
			if (nfill != m) {
				cout << "ERROR: squares do not make a connected section" << endl; return 8; }
		}
return 42;
}