#include <bits/stdc++.h>

using namespace std;

const int BUFFER_SIZE = 1 << 20;
char rb[BUFFER_SIZE], *rp = rb, *rt = rb;
inline char read_char() {
    return rp == rt ? (rt = rb + fread(rb, 1, BUFFER_SIZE, stdin), rp = rb, *rp ++) : *rp ++;
}
inline int read_int() {
    int x = 0;
    char ch = read_char(), flag = 0;

    while (ch != '-' && (ch < '0' || ch > '9')) {
        ch = read_char();
    }

    if (ch == '-') {
        flag = 1;
        ch = read_char();
    }

    for (x = 0; ch >= '0' && ch <= '9'; ch = read_char()) {
        x = x * 10 + (ch - '0');
    }

    return flag ? -x : x;
}

const int MAX_N = 100000 + 5;

int N, M, K;
int elast[MAX_N], ey[MAX_N << 1], enext[MAX_N << 1];
int fath[MAX_N], siz[MAX_N], dep[MAX_N], son[MAX_N], anc[MAX_N], dfn[MAX_N][2], dfn_;
int nv, ver[MAX_N], f[MAX_N], fcnt;

void dfs_tcp_1(int u, int fa) {
    fath[u] = fa, siz[u] = 1, dep[u] = dep[fa] + 1;

    for (int j = elast[u], v; j; j = enext[j]) {
        if ((v = ey[j]) != fa) {
            dfs_tcp_1(v, u);
            siz[u] += siz[v];
            son[u] = siz[son[u]] < siz[v] ? v : son[u];
        }
    }
}
void dfs_tcp_2(int u, int anc_) {
    anc[u] = anc_, dfn[u][0] = ++ dfn_;

    if (son[u])
        dfs_tcp_2(son[u], anc_);

    for (int j = elast[u], v; j; j = enext[j]) {
        if ((v = ey[j]) != fath[u] && v != son[u]) {
            dfs_tcp_2(v, v);
        }
    }

    dfn[u][1] = dfn_;
}
inline int get_lca(int u, int v) {
    while (anc[u] != anc[v]) {
        if (dep[anc[u]] > dep[anc[v]]) {
            u = fath[anc[u]];
        } else {
            v = fath[anc[v]];
        }
    }

    return dep[u] < dep[v] ? u : v;
}
inline bool cmp_by_dfn(int u, int v) {
    return dfn[u][0] < dfn[v][0];
}
void dfs_sum(int u, int fa) {
    for (int j = elast[u], v; j; j = enext[j]) {
        if ((v = ey[j]) != fa) {
            dfs_sum(v, u);
            f[u] += f[v];
        }
    }

    fcnt += f[u] >= K << 1;
}

int main() {
    N = read_int(), M = read_int(), K = read_int();

    for (int i = 1, j = 2; i < N; i ++) {
        int x = read_int(), y = read_int();
        ey[j] = y, enext[j] = elast[x], elast[x] = j ++;
        ey[j] = x, enext[j] = elast[y], elast[y] = j ++;
    }

    dfs_tcp_1(1, 0);
    dfs_tcp_2(1, 1);

    for (int i = 1; i <= M; i ++) {
        nv = read_int();

        for (int j = 1; j <= nv; j ++) {
            ver[j] = read_int();
        }

        sort(ver + 1, ver + 1 + nv, cmp_by_dfn);
        ver[0] = ver[nv];

        for (int i = 1; i <= nv; i ++) {
            int x = get_lca(ver[i - 1], ver[i]);
            f[ver[i - 1]] ++, f[ver[i]] ++, f[x] -= 2;
        }
    }

    dfs_sum(1, 0);
    printf("%d\n", fcnt);

    for (int i = 1, j = 1; i < N; i ++) {
        int x = ey[i << 1 | 1], y = ey[i << 1];

        if ((x == fath[y] ? f[y] : f[x]) >= K << 1) {
            printf("%d%c", i, j ++ < fcnt ? ' ' : '\n');
        }
    }

    return 0;
}