//Слава Україні, Героям слава

#include <bits/stdc++.h>

using namespace std;

const int N = 2e5 + 7;

int par[N], sz[N];
stack<tuple<int, int, int, int>> st;

int find(int a) {
    return a == par[a] ? a : find(par[a]);
}

bool unite(int a, int b) {
    if((a = find(a)) == (b = find(b))) {
        return false;
    }
    if(sz[b] > sz[a]) {
        swap(a, b);
    }
    st.push({a, sz[a], b, par[b]});
    sz[a] += sz[b];
    par[b] = a;
    return true;
}

void roll_back() {
    auto [a, b, c, d] = st.top(); st.pop();
    par[c] = d;
    sz[a] = b;
}

int n, m, k;
vector<pair<int, int>> edges, q;
vector<int> ans;

void bs(int l, int r, vector<int> &cand) {
    if(l + 1 == r or cand.empty()) {
        for(auto e : cand) {
            ans[e] = l + 1;
        }
        return;
    }
    int mid = (l + r) >> 1, cnt = 0;
    for(int i = l; i < mid; i++) {
        if(unite(edges[i].first, edges[i].second)) {
            cnt++;
        }
    }
    vector<int> pode, npode;
    for(auto e : cand) {
        if(find(q[e].first) == find(q[e].second)) {
            pode.push_back(e);
        } else {
            npode.push_back(e);
        }
    }
    for(int i = 0; i < cnt; i++) {
        roll_back();
    }
    bs(l, mid, pode);
    vector<int>().swap(pode);
    cnt = 0;
    for(int i = l; i < mid; i++) {
        if(unite(edges[i].first, edges[i].second)) {
            cnt++;
        }
    }
    bs(mid, r, npode);
    vector<int>().swap(npode);
    for(int i = 0; i < cnt; i++) {
        roll_back();
    }
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    for(int i = 0; i < N; i++) {
        par[i] = i;
        sz[i] = 1;
    }
    cin >> n >> m >> k;
    edges.resize(m);
    q.resize(k);
    ans.resize(k);
    for(int i = 0; i < m; i++) {
        cin >> edges[i].first >> edges[i].second;
    }
    for(int i = 0; i < k; i++) {
        cin >> q[i].first >> q[i].second;
    }
    vector<int> cand(k);
    iota(cand.begin(), cand.end(), 0);
    bs(0, m + 1, cand);
    for(int i = 0; i < k; i++) {
        if(q[i].first == q[i].second) {
            ans[i] = 0;
        }
        cout << (ans[i] == m + 1 ? -1 : ans[i]) << "\n";
    }
    return 0;
}