#include <iostream>
#include <queue>
#include <vector>

using namespace std;
using pii = pair<int, int>;

int main() {
  int n, m, q;
  cin >> n >> m >> q;
  vector<vector<int>> restsbyval(101);
  vector<int> rests(n + 1);
  for (int i = 1; i <= n; i++) {
    int w;
    cin >> w;
    rests[i] = w;
    restsbyval[w].push_back(i);
  }
  vector<vector<int>> graph(n + 1);
  for (int i = 0; i < m; i++) {
    int u, v;
    cin >> u >> v;
    graph[u].push_back(v);
    graph[v].push_back(u);
  }
  vector<vector<pii>> toursbyval(101);
  vector<int> ans(q);
  for (int i = 0; i < q; i++) {
    int p, a;
    cin >> p >> a;
    toursbyval[a].push_back({i, p});
  }

  vector<int> bq;
  for (int w = 1; w <= 100; w++) {
    vector<bool> visited(n + 1);
    vector<int> dists(n + 1, -1);
    for (int u : restsbyval[w]) {
      bq.push_back(u);
    }
    queue<int> qu;
    for (int x : bq) {
      dists[x] = 0;
      qu.push(x);
      visited[x] = true;
    }
    while (!qu.empty()) {
      int u = qu.front();
      qu.pop();
      for (int v : graph[u]) {
        if (visited[v])
          continue;
        dists[v] = dists[u] + 1;
        visited[v] = true;
        qu.push(v);
      }
    }
    for (auto x : toursbyval[w]) {
      ans[x.first] = dists[x.second];
    }
  }
  for (int x : ans)
    cout << x << endl;
}