#include <bits/stdc++.h>
#define int long long
//#define endl "\n" // fflush(stdout);
#define ALL(v) (v).begin(),(v).end()
#define Vi vector<int>
#define VVi vector<Vi>
#define VVVi vector<VVi>
#define Vm vector<mint>
#define Vs vector<string>
#define Vd vector<double>
#define Vc vector<char>
#define Pii pair<int,int>
#define Pdd pair<double,double>
#define VPii vector<Pii>
#define Tiii tuple<int,int,int>
#define VTiii vector<Tiii>
#define PQi priority_queue<int>
#define PQir priority_queue<int,vector<int>,greater<int>>
#define pb push_back
#define mp make_pair
#define mt make_tuple
#define itos to_string
#define stoi stoll
#define FI first
#define SE second
#define cYES cout<<"YES"<<endl
#define cNO cout<<"NO"<<endl
#define cYes cout<<"Yes"<<endl
#define cNo cout<<"No"<<endl
#define cyes cout<<"yes"<<endl
#define cno cout<<"no"<<endl
#define sortr(v) sort(v,greater<>())
#define rep(i,a,b) for(int i=a;i<b;i++)
#define repeq(i,a,b) for(int i=a;i<=b;i++)
#define repreq(i,a,b) for(int i=a;i>=b;i--)
#define dem(a,b) ((a+b-1)/(b))
#define INF 3000000000000000000 // 3.0*10^18
#define MAX LLONG_MAX
#define PI acos(-1.0L)
//int MOD = 998244353; // case
const int MOD = 1000000007; // 10^9 + 7
const double EPS = 1e-6;

using namespace std;

struct mint{int x;mint(int x=0):x((x%MOD+MOD)%MOD){}
mint operator-()const{return mint(-x);}
mint& operator+=(const mint a){if((x+=a.x)>=MOD)x-=MOD;return*this;}
mint& operator-=(const mint a){if((x+=MOD-a.x)>=MOD)x-=MOD;return*this;}
mint& operator*=(const mint a){(x*=a.x)%=MOD;return*this;}
mint operator+(const mint a)const{return mint(*this)+=a;}
mint operator-(const mint a)const{return mint(*this)-=a;}
mint operator*(const mint a)const{return mint(*this)*=a;}
mint pow(int t)const{if(!t)return 1;mint a=pow(t>>1);a*=a;if(t&1)a*=*this;return a;}
mint inv()const{return pow(MOD-2);}
mint& operator/=(const mint a){return*this*=a.inv();}
mint operator/(const mint a)const{return mint(*this)/=a;}};
ostream& operator<<(ostream& os, const mint& a) {return os << a.x;}

/* debug */
template <typename T> // vector
ostream& operator<<(ostream& os,const vector<T> &V){int N=V.size();
if(N==0){os<<'.';return os;}rep(i,0,N-1){os<<V[i]<<' ';}os<<V[N-1];return os;}
template <typename T> // vector vector
ostream& operator<<(ostream& os,const vector<vector<T>> &V){
int N=V.size();rep(i,0,N-1)cout<<V[i]<<endl;cout<<V[N-1];return os;}
template <typename T,typename S> // pair
ostream& operator<<(ostream& os, pair<T,S> const&P){os<<P.FI<<' '<<P.SE;return os;}
template <typename T> // set
ostream& operator<<(ostream& os,set<T> &S){auto it=S.begin();while(it!=S.end()){
os<<*it;if(next(it,1)!=S.end())os<<' ';it++;};return os;}
template <typename T> // deque
ostream& operator<<(ostream& os, deque<T> &q){for(auto it=q.begin();it<q.end();it++){
os<<*it;if(it+1!=q.end())os<<" ";}return os;}

/* useful */
template<typename T>void Vin(vector<T> &v){int n=v.size();rep(i,0,n)cin>>v[i];}
int gcd(int a,int b){return b?gcd(b,a%b):a;}
int lcm(int a,int b){return a/gcd(a,b)*b;}
int mypow(int x, int n, int m){
if(n==0)return 1;if(n%2==0)return mypow(x*x%m,n/2,m);else return x*mypow(x,n-1,m)%m;}
int scomb(int n, int r){if(r<0||r>n)return 0;if((n-r)<r)r=n-r; // nCr
int a=1;for(int i=n;i>n-r;--i){a=a*i;}for(int i=1;i<r+1;++i){a=a/i;}return a;}
Vi vis(Vi &v){Vi S(v.size()+1);rep(i,1,S.size())S[i]+=v[i-1]+S[i-1];return S;}
int digit_sum(int n){int ret=0; while(n>0){ret+=n%10;n/=10;}return ret;}
int digit(int k,int i){string s = itos(k);return s[s.size()-i]-'0';} // i桁目の数字
template<typename T>void press(T &v){v.erase(unique(ALL(v)),v.end());} // 圧縮
Vi zip(Vi b){int Z=b.size(); // 座標圧縮
Pii p[Z+10];int a=b.size();Vi l(a);for(int i=0;i<a;i++)
p[i]=mp(b[i],i);sort(p,p+a);int w=0;for(int i=0;i<a;i++)
{if(i&&p[i].first!=p[i-1].first)w++;l[p[i].second]=w;}return l;}
Vi nibe2V(){Vi a(60);int q = 1;rep(i,0,60){a[i]=q;q*=2;}return a;}
//Vi nibe = nibe2V(); // 2^n
int modiv(int a,int b){return a*mypow(b,MOD-2,MOD)%MOD;} // a÷b(%MOD)
int SMALLER(Vi &a,int x){return lower_bound(a.begin(),a.end(),x)-a.begin();}
int orSMALLER(Vi &a,int x){return upper_bound(a.begin(),a.end(),x)-a.begin();}
int BIGGER(Vi &a,int x){return a.size()-orSMALLER(a,x);}
int orBIGGER(Vi &a,int x){return a.size()-SMALLER(a,x);}
int COUNT(Vi &a,int x) {return upper_bound(ALL(a),x)-lower_bound(ALL(a),x);}
int maxind(Vi &a){return max_element(ALL(a))-a.begin();}
int minind(Vi &a){return min_element(ALL(a))-a.begin();}
Vi stpowV(){Vi a(1000005);a[0]=1;repeq(i,1,1000004)a[i]=a[i-1]*i%MOD;return a;}
//Vi stpow = stpowV(); // 階乗配列(%MOD)

/****************************** START ******************************/

using uint = unsigned;
using ll = long long;
using ull = unsigned long long;
constexpr ll TEN(int n) { return (n == 0) ? 1 : 10 * TEN(n - 1); }
template <class T> using V = vector<T>;
template <class T> using VV = V<V<T>>;

template <class D, class I> struct StaticRangeSum {
    struct P {
        I x, y;
        D val;
    };
    int lg;
    V<I> xs, ys;
    V<int> mid;
    VV<int> bits;
    VV<D> sums;
    StaticRangeSum(){}
    StaticRangeSum(V<P> ps) {
        if (!ps.size()) return;
        sort(ps.begin(), ps.end(), [&](P l, P r) { return l.x < r.x; });
        for (auto p : ps) {
            xs.push_back(p.x);
            ys.push_back(p.y);
        }
        sort(ys.begin(), ys.end());
        ys.erase(unique(ys.begin(), ys.end()), ys.end());
        int n = (int)(xs.size());
        int m = (int)(ys.size());
        lg = 1;
        while ((1 << lg) < m) lg++;
        mid = V<int>(lg);
        bits = VV<int>(lg, V<int>(n + 1));
        sums = VV<D>(lg + 1, V<D>(n + 1));
        struct Q {
            int y;
            D val;
        };
        V<Q> v;
        for (auto p: ps) {
            int y = (int)(lower_bound(ys.begin(), ys.end(), p.y) - ys.begin());
            v.push_back({y, p.val});
        }
        for (int i = 0; i < n; i++) {
            Q q = v[i];
            sums[lg][i + 1] = sums[lg][i] + q.val;
        }
        for (int lv = lg - 1; lv >= 0; lv--) {
            array<V<Q>, 2> nx;
            for (int i = 0; i < n; i++) {
                Q q = v[i];
                bool f = (q.y >> lv) & 1;
                bits[lv][i + 1] = bits[lv][i] + (f ? 0 : 1);
                nx[f].push_back(q);
            }
            mid[lv] = (int)(nx[0].size());
            v.clear();
            v.insert(v.end(), nx[0].begin(), nx[0].end());
            v.insert(v.end(), nx[1].begin(), nx[1].end());
            for (int i = 0; i < n; i++) {
                Q q = v[i];
                sums[lv][i + 1] = sums[lv][i] + q.val;
            }
        }
    }
    D sum(int l, int r, int u) {
        if (u == (1 << lg)) return sums[lg][r] - sums[lg][l];
        D ans = 0;
        for (int lv = lg - 1; lv >= 0; lv--) {
            bool f = (u >> lv) & 1;
            int l0 = bits[lv][l], r0 = bits[lv][r];
            if (f) {
                ans += sums[lv][r0] - sums[lv][l0];
                l = l - l0 + mid[lv];
                r = r - r0 + mid[lv];
            } else {
                l = l0;
                r = r0;
            }
        }
        return ans;
    }
    D sum(I _lx, I _ly, I _ux, I _uy) {
        assert(_lx <= _ux && _ly <= _uy);
        int lx = (int)(lower_bound(xs.begin(), xs.end(), _lx) - xs.begin());
        int ux = (int)(lower_bound(xs.begin(), xs.end(), _ux) - xs.begin());
        int ly = (int)(lower_bound(ys.begin(), ys.end(), _ly) - ys.begin());
        int uy = (int)(lower_bound(ys.begin(), ys.end(), _uy) - ys.begin());
        if (lx == ux || ly == uy) return D(0);
        return sum(lx, ux, uy) - sum(lx, ux, ly);
    }
};

struct SUM2D {
  
  int n;
  int nowi;
  vector<StaticRangeSum<ll, int>::P> ps;
  StaticRangeSum<ll, int> srs;
  
  SUM2D(){}
  SUM2D(int ct) {init(ct);} // 宣言の際にポイント数を入力
  
  void init(int ct){
    n = ct;
    ps = V<StaticRangeSum<ll, int>::P>(ct);
    nowi = 0;
  }
  
  void add(int x,int y,int val){
    ps[nowi].x = x;
    ps[nowi].y = y;
    ps[nowi].val = val;
    nowi++;
    if(n==nowi) srs = StaticRangeSum<ll, int>(ps);
  }
  
  int sum(int l,int d,int r,int u){
    r++;u++;
    return srs.sum(l, d, r, u);
  }
  /*　使い方まとめ　*/ 
  /*
  SUM2D pl(n) // 宣言 n は平面上の点の個数
  pl.add(x,y,val) // どちらも正の座標 (x,y) に val 個の点を追加
  pl.sum(a,b,c,d) // 縦a~c，横b~dの長方形区間内の点の個数を求める(0-index)
  */
};

struct RinR {
  
  int N;
  int ct;
  SUM2D pl;
  
  RinR(int n) {
    N = n;
    pl = SUM2D(n);
    ct = 0;
  }
  
  void add(int l,int r) {
    ct++;
    pl.add(l,r,1);
  }
  
  int sum(int l,int r) {
    if(ct!=N) return -1;
    else return pl.sum(l,l,r,r);
  }
  /* 使い方 */
  /*
  RinR rr(n) // 宣言 n は区間数
  rr.add(l,r) // [l,r]の区間を追加
  rr.sum(l,r) // [l,r]内の区間数を返す（※注意 ちょうどn回addしたときのみ可）
  */
};

signed main() {
  cin.tie(0);cout.tie(0);ios::sync_with_stdio(false);cout<<fixed<<setprecision(12);
  int n,m,q;cin >> n >> m >> q;
  RinR rr(m);
  rep(i,0,m){
    int qw,er;cin >> qw >> er;qw--,er--;
    rr.add(qw,er);
  }
  rep(i,0,q){
    int qw,er;cin >> qw >> er;qw--,er--;
    cout << rr.sum(qw,er) << endl;
  }
  return 0;
}

Measured memory_bytes: 55900