public static int countPath3(int m, int n) {
		if (m < 0 || n < 0) {
			return 0;
		}
		if (m == 0 && n == 0) {
			return 1;
		}
		if (m == 0 && n != 0) {
			return 1;
		}
		if (n == 0 && m != 0) {
			return 1;
		}
		return countPath3(m - 1, n) + countPath3(m, n - 1);
	}