#include <bits/stdc++.h>
using namespace std;

using ll = long long;

template <class T> using vc = vector<T>;
using vi = vc<int>;
using vl = vc<ll>;
template <class T> using vv = vc<vc<T>>;
using vvi = vv<int>;
using vvl = vv<ll>;
using vs = vc<string>;
using P = pair<ll, ll>;

const int INF = 1e9;
const ll INF_ll = 1LL << 60;
vl dx = {1, 0, -1, 0}; // vl dx = {1,1,0,-1,-1,-1,0,1};
vl dy = {0, 1, 0, -1}; // vl dx = {0,1,1,1,0,-1,-1,-1};

using ld = long double;

#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rep1(i, n) for (int i = 1; i <= (int)(n); i++)
#define drep(i, n) for (int i = (int)(n)-1; i >= 0; i--)
#define drep1(i, n) for (int i = (int)(n); i >= 1; i--)
#define nfor(i, s, n) for (ll i = s; i < (ll)(n); i++)      // i=s,s+1...n-1 ノーマルfor
#define dfor(i, s, n) for (ll i = (s)-1; i >= (ll)(n); i--) // s-1スタートでnまで落ちる
#define fore(c, s) for (auto c : s)                         // for_each

#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define chmax(x, y) x = max(x, y)
#define chmin(x, y) x = min(x, y)
#define YES cout << "Yes" << endl
#define NO cout << "No" << endl
#define YN                                                                                         \
    { cout << "Yes" << endl; }                                                                     \
    else {                                                                                         \
        cout << "No" << endl;                                                                      \
    }
#define dame cout << -1 << endl
#define vc_unique(v) v.erase(unique(v.begin(), v.end()), v.end());

bool out_grid(ll i, ll j, ll h, ll w) { // trueならcontinueする
    return (!(0 <= i && i < h && 0 <= j && j < w));
}

ll nc2(ll x) { return x * (x - 1) / 2; }
ll nc3(ll x) { return x * (x - 1) * (x - 2) / 6; }

// const int mint = 998244353;
// const int mint = 1000000007;

int main() {
    int N, M;
    cin >> N >> M;
    vvi G(N);
    rep(i, M) {
        int u, v;
        cin >> u >> v;
        u--;
        v--;
        G[u].emplace_back(v);
        G[v].emplace_back(u);
    }
    int L;
    cin >> L;
    vi dist(N, 0);
    queue<int> qu;
    rep(i, L) {
        int j, k;
        cin >> j >> k;
        j--;
        qu.push(j);
        dist[j] = k + 1;
    }
    // 幅優先探索
    while (!qu.empty()) {
        int pos = qu.front();
        qu.pop();
        for (auto nx : G[pos]) {
            if (dist[pos] - 1 > dist[nx]) {
                dist[nx] = dist[pos] - 1;
                qu.push(nx);
            }
        }
    }
    if (dist[0] != 0) {
        NO;
        return 0;
    }
    qu.push(0);
    vc<int> dist2(N, -1);
    dist2[0] = 0;
    while (!qu.empty()) {
        int pos = qu.front();
        qu.pop();
        for (auto nx : G[pos]) {
            if (dist[nx] != 0) continue;
            if (dist2[nx] != -1) continue;
            qu.push(nx);
            dist2[nx] = dist2[pos] + 1;
        }
    }
    if (dist2[N - 1] == -1) {
        NO;
        return 0;
    }
    YES;
    cout << dist2[N - 1] << endl;

    return 0;
}