from heapq import heappop, heappush
from collections import deque


N, M = map(int, input().split())
g = [[] for _ in range(N)]
for _ in range(M):
    u, v = map(int, input().split())
    u, v = u - 1, v - 1
    g[u].append(v)
    g[v].append(u)
L = int(input())
R = [-1] * N
hq = []
for _ in range(L):
    j, k = map(int, input().split())
    j -= 1
    R[j] = k
    heappush(hq, (-k, j))

while hq:
    k, u = heappop(hq)
    k = -k
    if R[u] > k:
        continue
    for v in g[u]:
        if R[v] < k - 1:
            R[v] = k - 1
            heappush(hq, (-(k - 1), v))

if R[0] != -1:
    print("No")
    exit()

que = deque([0])
dist = [-1] * N
dist[0] = 0
while que:
    u = que.popleft()
    for v in g[u]:
        if dist[v] == R[v] == -1:
            dist[v] = dist[u] + 1
            que.append(v)

if dist[-1] == -1:
    print("No")
else:
    print("Yes")
    print(dist[-1])