#include <iostream>
#include<cstdio>
#include<vector>
#include<cstring>
#include<queue>
#include<algorithm>
using namespace std;
typedef pair<int,int>PII;
const int INF=100000;
const int maxn=1000+5;
struct Edge{
int to,weight;
Edge(int to,int weight):to(to),weight(weight) {}
};
int v,e;
int d[maxn];
vector<Edge>G[maxn];
bool done[maxn];
void dijkstra(int start)
{
    memset(done,false,sizeof(done));
    for(int i=1;i<=v;i++)
        d[i]=(i==start?0:INF);
    priority_queue<PII,vector<PII>,greater<PII> >pq;
    pq.push(PII(d[start],start));
    while(!pq.empty())
    {
        PII k=pq.top();
        pq.pop();
        int distance=k.first;
        int vist=k.second;
        if(done[vist]) continue;
        done[vist]=true;
        for(int i=0;i<G[vist].size();i++)
        {
            int k=G[vist][i].to;
            if(d[k]>d[vist]+G[vist][i].weight)
            {
                d[k]=d[vist]+G[vist][i].weight;
                pq.push(PII(d[k],k));
            }
        }
    }
}
int main()
{
    scanf("%d%d",&v,&e);
    for(int i=0;i<e;i++)
    {
        int v1,v2,dist;
        scanf("%d%d%d",&v1,&v2,&dist);
        /*避免重邊*/
        bool flag=false;
        for(int i=0;i<G[v1].size();i++)
        {
            if(G[v1][i].to==v2) {
                                            flag=true;
                                            if(dist<G[v1][i].weight) G[v1][i].weight=dist;
                                            break;
                                         }
        }
        if(!flag) G[v1].push_back(Edge(v2,dist));
    }
    int start,end;
    while(scanf("%d%d",&start,&end)==2)
    {
        dijkstra(start);
        if(d[end]>=INF) printf("No\n");
        else {
                printf("Yes\n");
                printf("%d\n",d[end]);
        }
    }
    return 0;
}