#include<iostream> #include<vector> #include<algorithm> using namespace std; using ll = long long; #include<queue> #include<atcoder/scc> int main(){ cin.tie(nullptr); ios::sync_with_stdio(false); ll n,m,q; cin>>n>>m>>q; vector<vector<int>> g(n); vector<ll> u(m),v(m),w(m); for(int i = 0;i<m;i++){ cin>>u[i]>>v[i]>>w[i]; u[i]--;v[i]--; g[u[i]].push_back(i); } vector<int> now(m,0); while(q--){ { int j; cin>>j; j--; now[j] ^= 1; } atcoder::scc_graph s(n); { for(int i = 0;i<m;i++) if(now[i]==0) s.add_edge(u[i],v[i]); } auto use = s.scc(); vector<int> cnt(n,0); for(int i = 0;i<use.size();i++) for(int j:use[i]) cnt[j] = i; vector<ll> can(n,-1e18); can[0] = 0; for(auto p:use){ priority_queue<pair<ll,ll>,vector<pair<ll,ll>>,greater<pair<ll,ll>>> que; for(int j:p) if(can[j]>=-1e8) que.push({can[j],j}); while(que.size()){ int ni = que.top().second; auto nn = que.top(); que.pop(); if(nn.first!=can[ni]) continue; for(auto id:g[ni]){ int to = v[id]; if(now[id]==1) continue; if(cnt[to]==cnt[ni]){ if(can[to]<can[ni]+w[id]){ can[to] = can[ni] + w[id]; que.push({can[to],to}); } }else{ can[to] = max(can[to],can[ni]+w[id]); } } } } ll ans = can[n-1]; if(ans<-1e8) cout<<"NaN\n"; else cout<<ans<<endl; } }