ArrayList<Integer> graph[];
	int[] c;
	int[] parentColor;

	void solve() throws IOException {
		int n = rI();
		this.graph = new ArrayList[n];
		for (int i = 0; i < n; i++) {
			graph[i] = new ArrayList<Integer>();
		}
		for (int i = 0; i < n - 1; i++) {
			int a = rI() - 1;
			int b = rI() - 1;
			graph[a].add(b);
			graph[b].add(a);
		}
		this.parentColor = new int[n];
		this.c = rA(n);
		this.used = new boolean[n];
		this.listForCheckSecond = new ArrayList<Integer>();
		this.listForCheckFirst = new ArrayList<Integer>();
		this.edge = 0;
		this.firstColor = c[0];
		this.secondColor = -2;
		this.f = false;
		dfs(0);
		Arrays.fill(used, false);
		dfs2(edge);
		if (f) {
			Arrays.fill(used, false);
			edge = 0;
			f = false;
			dfs2(0);
			if (f) {
				out.print("NO");
			} else {
				out.println("YES");
				out.println("1");
			}
		} else {
			out.println("YES");
			out.println(edge + 1);
		}

	}

	int edge;
	boolean[] used;
	ArrayList<Integer> listForCheckSecond;
	ArrayList<Integer> listForCheckFirst;
	int firstColor;
	int secondColor;
	boolean f;

	// =======================================================
	void dfs(int from) {
		used[from] = true;
		for (int i : graph[from]) {
			if (!used[i]) {
				if (c[i] != firstColor) {
					if (edge == 0) {
						edge = i;
						continue;
					} else {
						f = true;
						return;
					}
				} else {
					dfs(i);
				}

			}
		}
	}

	void dfs2(int from) {
		used[from] = true;
		for (int i : graph[from]) {
			if (!used[i]) {
				if (from == edge || c[from] == c[i]) {
					dfs2(i);
				} else {
					f = true;
					return;
				}
			}
		}
	}