//多始点BFS(嘘解法)
#include <iostream>
#include <algorithm>
#include <atcoder/all>
#include <queue>
using namespace std;
using namespace atcoder;
using ll = long long;
//#define endl "\n";
ll N, M, L;
vector<vector<int>> G;

int main(){
  cin >> N >> M;
  G.resize(N + 1);
  for(int i = 0; i < M; i++){
    ll a, b;
    cin >> a >> b;
    G[a].push_back(b);
    G[b].push_back(a);
  }
  cin >> L;
  queue<pair<ll, ll>> quep;
  vector<ll> chk(N + 1, -1);
  for(int i = 0; i < L; i++){
    ll j, k;
    cin >> j >> k;
    chk[j] = k;
    quep.push({j, chk[j]});
  }
  while(!quep.empty()){
    auto [pos, d] = quep.front(); quep.pop();
    for(auto to: G[pos]){
      if(chk[to] < d - 1){
        chk[to] = d - 1;
        quep.push({to, chk[to]});
      }
    }
  }
  queue<ll> que;
  vector<ll> dist(N + 1, -1);
  if(chk[1] != -1){
    cout << "No" << endl;
  }else{
    dist[1] = 0;
    que.push(1);
    while(!que.empty()){
      int pos = que.front(); que.pop();
      for(auto to: G[pos]){
        if(dist[to] == -1 && chk[to] == -1){
          dist[to] = dist[pos] + 1;
          que.push(to);
        }
      }
    }
    if(dist[N] == -1){
      cout << "No" << endl;
    }else{
      cout << "Yes" << endl;
      cout << dist[N] << endl;
    }
  }
  return 0;
}