C

#include <iostream>
#include <iomanip>
#include <vector>
#include <array>
#include <set>

using namespace std;

#define int long long

const long long INF = 1e18 + 7;
const int MAXN = 1e5 + 100;
const int N = 1e5 + 10;
const int MOD = 1e9 + 7;

int dp[MAXN][3];
array<int, MAXN> color, used;
vector<vector<int>> g;

void dfs(int v, int p) {
    used[v] = true;
    array<int, 3> mx = {1, 1, 1};
    for (auto to: g[v]) {
        if (!used[to]) {
            dfs(to, v);
        }
        if (to != p) {
            mx[0] *= (dp[to][1] + dp[to][2]) % MOD;
            mx[0] %= MOD;

            mx[1] *= (dp[to][0] + dp[to][2]) % MOD;
            mx[1] %= MOD;

            mx[2] *= (dp[to][0] + dp[to][1]) % MOD;
            mx[2] %= MOD;
        }
    }
    if (color[v] != -1) {
        dp[v][color[v]] = mx[color[v]];
    } else {
        dp[v][0] = mx[0];
        dp[v][1] = mx[1];
        dp[v][2] = mx[2];
    }
}

signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    freopen("barnpainting.in", "r", stdin);
    freopen("barnpainting.out", "w", stdout);
    int n, k;
    cin >> n >> k;
    g.resize(n);
    for (int i = 0; i < n - 1; ++i) {
        int u, v;
        cin >> u >> v;
        --u, --v;
        g[u].emplace_back(v);
        g[v].emplace_back(u);
    }
    color.fill(-1);
    for (int i = 0; i < k; ++i) {
        int v, col;
        cin >> v >> col;
        --v, --col;
        color[v] = col;
    }
    dfs(0, -1);
    cout << ((dp[0][0] + dp[0][1]) % MOD + dp[0][2]) % MOD << '\n';
}