#include <iostream>
#include <vector>
#include <map>

using namespace std;

typedef unsigned long long ull;

int INF = 2147483640;

void get_path(int i, int j, const vector<vector<int>> &next, vector<int> &path) {
    int temp = i;
    while (temp != j) {
        path.push_back(temp);
        temp = next[temp][j];
    }
    path.push_back(j);
}

int main() {
    int n, m, c;
    cin >> n >> m >> c;
    map<pair<int, int>, int> e;
    vector<vector<int>> g(n, vector<int>(n, INF));
    vector<vector<int>> next(n, vector<int>(n, 0));
    for (int i = 0; i < n; ++i) {
        for (int j = 0; j < n; ++j) {
                next[i][j] = j;
        }
    }
    for (int i = 0; i < m; ++i) {
        int f, s;
        cin >> f >> s;
        f--;
        s--;
        int w;
        cin >> w;
        g[f][s] = -w;
        next[f][s] = s;
        e[make_pair(f, s)] = i + 1;
    }

    for (int k = 0; k < n; ++k) {
        for (int i = 0; i < n; ++i) {
            for (int j = 0; j < n; ++j) {
                if (g[i][k] < INF && g[k][j] < INF) {
                    if (g[i][k] + g[k][j] < g[i][j]) {
                        g[i][j] = g[i][k] + g[k][j];
                        next[i][j] = next[i][k];
                    }
                }
            }
        }
    }
    int from, to;
    cin >> from;
    cin >> to;
    from--;
    to--;
    if (g[from][from] < 0) {
        cout << "infinitely kind";
        return 0;
    }
    vector<int> path;
    path.push_back(from);
    for (int i = 1; i < c; ++i) {
        vector<int> path_temp;
        get_path(from, to, next, path_temp);
        for (int j = 0; j < path_temp.size(); ++j) {
            if (g[path_temp[j]][path_temp[j]] < 0) {
                cout << "infinitely kind";
                return 0;
            }
        }
        path.insert(
                path.end(),
                std::make_move_iterator(path_temp.begin() + 1),
                std::make_move_iterator(path_temp.end()));
        from = to;
        if (i != c - 1) {
            cin >> to;
            to--;
        }
    }
    cout << path.size() - 1 << '\n';
    for (auto i = 0; i < path.size() - 1; i++) {
        cout << e[make_pair(path[i], path[i + 1])] << ' ';
    }
}