#include<cstdio>#include<cstring>const int maxn(555);int g[maxn][maxn];int dist[maxn], vis[maxn];int n, p, c, m;const int inf(100000000);int ans[maxn];void dijk(){memset(vis, 0, sizeof vis);for(int i = 1; i <= n; i ++) dist[i] = inf;dist[1] = 0;for(int i = 0; i < n; i ++){int min = inf, u;for(int j = 1; j <= n; j ++){if(!vis[j] && dist[j] < min){min = dist[j];u = j;}}if(min == inf) break;vis[u] = 1;for(int j = 1; j <= n; j ++){if(!vis[j] && g[u][j] != inf) if(g[u][j] + dist[u] < dist[j])dist[j] = dist[u] + g[u][j];}}int cnt = 0;for(int i = 1; i <= c; i ++){int k;scanf("%d", &k);if(dist[k] <= m) ans[cnt++] = i;}printf("%dn", cnt);for(int i = 0; i < cnt; i ++) printf("%dn", ans[i]);}int main(){while(~scanf("%d%d%d%d", &n, &p, &c, &m)){for(int i = 1; i <= n; i ++)for(int j = 1; j <= n; j ++)if(i == j) g[i][j] = 0;else g[i][j] = inf;for(int i = 0; i < p; i ++){int u, v, w;scanf("%d%d%d", &u, &v, &w);if(w < g[u][v]){ g[u][v] = g[v][u] = w;}}dijk();}return 0;}
