#include <iostream>
#include <algorithm>
#include <vector>
#include <set>
using namespace std;

struct Edge {
    int a, b, w;
};

vector<Edge> g[100010];
int color[100010];

vector<long long> dfs(int from, int to, int n) {
    vector<long long> dist(n);
    dist[to] = 1LL << 60;

    fill(color, color + n, 0);
    color[from] = -1;

    for (int i = 0; i < g[from].size(); i++) {
        int v = g[from][i].b;
        long long d = g[from][i].w;
        while (v != to) {
            color[v] = i + 1;
            dist[v] = d;
            for (auto &e : g[v]) {
                if (!color[e.b]) {
                    v = e.b;
                    d += e.w;
                }
            }
        }
        dist[to] = min(dist[to], d);
    }

    return dist;
}

int main() {
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);

    int n, m, q;
    cin >> n >> m >> q;

    for (int i = 0; i < m; i++) {
        int a, b, w;
        cin >> a >> b >> w;
        g[a - 1].push_back({ a - 1, b - 1, w });
        g[b - 1].push_back({ b - 1, a - 1, w });
    }

    int beg = 0, end = n - 1;
    auto distBeg = dfs(beg, end, n);
    auto distEnd = dfs(end, beg, n);

    for (int qi = 0; qi < q; qi++) {
        int a, b;
        cin >> a >> b;
        a--;
        b--;

        long long res = 1LL << 60;
        res = min(res, distBeg[a] + distBeg[b]);
        res = min(res, distEnd[a] + distEnd[b]);
        res = min(res, distBeg[a] + distBeg[end] + distEnd[b]);
        res = min(res, distEnd[a] + distEnd[beg] + distBeg[b]);
        if (color[a] == color[b])
            res = min(res, max(distBeg[a], distBeg[b]) - min(distBeg[a], distBeg[b]));

        cout << res << " ";
    }
}