/* -*- coding: utf-8 -*-
 *
 * 3326.cc:  No.3326 蟯ｩ莠墓弌莠ｺ縺ｮ蟶ｰ譏・- yukicoder
 */

#include<cstdio>
#include<vector>
#include<queue>
#include<algorithm>
#include<utility>

using namespace std;

/* constant */

const int MAX_N = 200000;

/* typedef */

using vi = vector<int>;
using qi = queue<int>;
using pii = pair<int,int>;

/* global variables */

vi nbrs[MAX_N];
int js[MAX_N], ks[MAX_N];
int bs[MAX_N], ds[MAX_N];

/* subroutines */

/* main */

int main() {
  int n, m;
  scanf("%d%d", &n, &m);
  for (int i = 0; i < m; i++) {
    int u, v;
    scanf("%d%d", &u, &v);
    u--, v--;
    nbrs[u].push_back(v);
    nbrs[v].push_back(u);
  }
  int l;
  scanf("%d", &l);
  for (int i = 0; i < l; i++) scanf("%d%d", js + i, ks + i), js[i]--;

  priority_queue<pii> pq;
  for (int i = 0; i < l; i++) {
    bs[js[i]] = ks[i] + 1;
    if (ks[i] > 0) pq.push({ks[i] + 1, js[i]});
  }

  while (! pq.empty()) {
    auto [ub, u] = pq.top(); pq.pop();
    if (ub != bs[u]) continue;
    int vb = ub - 1;
    
    for (auto v: nbrs[u])
      if (bs[v] < vb) {
	bs[v] = vb;
	if (vb > 1) pq.push({vb, v});
      }
  }
  if (bs[0] > 0) { puts("No"); return 0; }
  //for (int i = 0; i < n; i++) printf(" %d", bs[i]); putchar('\n');
  
  fill(ds, ds + n, -1);
  ds[0] = 0;
  qi q;
  q.push(0);

  while (! q.empty()) {
    int u = q.front(); q.pop();
    if (u == n - 1) break;

    for (auto v: nbrs[u])
      if (ds[v] < 0 && bs[v] == 0)
	ds[v] = ds[u] + 1, q.push(v);
  }

  if (ds[n - 1] >= 0) printf("Yes\n%d\n", ds[n - 1]);
  else puts("No");
  
  return 0;
}