import java.io.*;
import java.util.*;
import java.util.function.*;
import java.util.stream.*;
import java.math.*;

public class Main {
    public static void main(String[] args) throws Exception {
        FastScanner sc = new FastScanner();
        int n = sc.nextInt();
        int m = sc.nextInt();
        List<List<Integer>> graph = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            graph.add(new ArrayList<>());
        }
        while (m-- > 0) {
            int a = sc.nextInt() - 1;
            int b = sc.nextInt() - 1;
            graph.get(a).add(b);
            graph.get(b).add(a);
        }
        int l = sc.nextInt();
        PriorityQueue<Path> queue = new PriorityQueue<>();
        while (l-- > 0) {
            queue.add(new Path(sc.nextInt() - 1, sc.nextInt()));
        }
        boolean[] distables = new boolean[n];
        while (queue.size() > 0) {
            Path p = queue.poll();
            if (distables[p.idx]) {
                continue;
            }
            distables[p.idx] = true;
            if (p.value == 0) {
                continue;
            }
            for (int x : graph.get(p.idx)) {
                queue.add(new Path(x, p.value - 1));
            }
        }
        Deque<Path> deq = new ArrayDeque<>();
        deq.add(new Path(0, 0));
        int[] costs = new int[n];
        Arrays.fill(costs, Integer.MAX_VALUE);
        while (deq.size() > 0) {
            Path p = deq.poll();
            if (costs[p.idx] <= p.value || distables[p.idx]) {
                continue;
            }
            costs[p.idx] = p.value;
            for (int x : graph.get(p.idx)) {
                deq.add(new Path(x, p.value + 1));
            }
        }
        if (costs[n - 1] == Integer.MAX_VALUE) {
            System.out.println("No");
        } else {
            System.out.println("Yes");
            System.out.println(costs[n - 1]);
        }
    }
    
    static class Path implements Comparable<Path> {
        int idx;
        int value;
        
        public Path(int idx, int value) {
            this.idx = idx;
            this.value = value;
        }
        
        public int compareTo(Path another) {
            return another.value - value;
        }
    }
}

class FastScanner {
    private DataInputStream din;
    private byte[] buffer;
    private int bufferPointer, bytesRead;
    private static final int BUFFER_SIZE = 1 << 16; // 65,536 バイト

    public FastScanner() {
        din = new DataInputStream(System.in);
        buffer = new byte[BUFFER_SIZE];
        bufferPointer = bytesRead = 0;
    }

    private byte read() {
        try {
            if (bufferPointer == bytesRead) {
                bytesRead = din.read(buffer, 0, BUFFER_SIZE);
                if (bytesRead == -1) return -1;
                bufferPointer = 0;
            }
            return buffer[bufferPointer++];
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    public String next() {
        byte b = read();
        // 空白文字を読み飛ばす
        while (isSpaceChar(b)) {
            b = read();
        }
        StringBuilder sb = new StringBuilder();
        while (!isSpaceChar(b)) {
            sb.append((char) b);
            b = read();
        }
        return sb.toString();
    }

    public int nextInt() {
        int ret = 0;
        byte c = read();
        while (isSpaceChar(c)) c = read();
        boolean neg = (c == '-');
        if (neg) c = read();
        do {
            ret = ret * 10 + c - '0';
            c = read();
        } while (!isSpaceChar(c));
        return neg ? -ret : ret;
    }

    public long nextLong() {
        long ret = 0;
        byte c = read();
        while (isSpaceChar(c)) c = read();
        boolean neg = (c == '-');
        if (neg) c = read();
        do {
            ret = ret * 10L + c - '0';
            c = read();
        } while (!isSpaceChar(c));
        return neg ? -ret : ret;
    }

    public double nextDouble() {
        double ret = 0, div = 1;
        byte c = read();
        while (isSpaceChar(c)) c = read();
        boolean neg = (c == '-');
        if (neg) c = read();
        do {
            ret = ret * 10 + c - '0';
            c = read();
        } while (!isSpaceChar(c) && c != '.');
        if (c == '.') {
            while (!isSpaceChar(c = read())) {
                ret += (c - '0') / (div *= 10);
            }
        }
        return neg ? -ret : ret;
    }

    private boolean isSpaceChar(byte c) {
        return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    }

    public void close() {
        try {
            if (din != null) din.close();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}