1 #include <cstdio>
  2 #include <cstring>
  3 #include <algorithm>
  4 using namespace std;
  5 
  6 const int HLEN = 10000010;
  7 const int LEN = 20020;
  8 
  9 struct line
 10 {
 11     int left;
 12     int right;
 13     int value;
 14 }line[LEN*4];
 15 
 16 struct input
 17 {
 18     int a, b;
 19 }in[LEN>>1];  //用于记录输入的数据
 20 int sub[LEN]; //用于离散化
 21 
 22 short hash[HLEN]; //用于储存离散后的映射关系
 23 int ans = 0;
 24 bool poster[LEN];
 25 
 26 void buildt(int l, int r, int step)
 27 {
 28     line[step].left = l;
 29     line[step].right = r;
 30     line[step].value = 0;
 31     if (l == r)
 32         return;
 33     int mid = (l + r)>>1;
 34     buildt(l, mid, step<<1);
 35     buildt(mid+1, r, step<<1|1);
 36 }
 37 
 38 void pushdown(int step)
 39 {
 40     line[step<<1].value = line[step<<1|1].value = line[step].value;
 41     line[step].value = 0;
 42 }
 43 
 44 void update(int l, int r, int value, int step)
 45 {
 46     if (line[step].left == l && line[step].right == r){
 47         line[step].value = value;
 48         return;
 49     }
 50     if (line[step].value != 0 && line[step].value != value) //如果当前位置已被涂过色，则向下更新
 51         pushdown(step);
 52     int mid = (line[step].left + line[step].right)>>1;
 53     if (r <= mid)
 54         update(l, r, value, step<<1);
 55     else if (l > mid)
 56         update(l, r, value, step<<1|1);
 57     else{
 58         update(l, mid, value, step<<1);
 59         update(mid+1, r, value, step<<1|1);
 60     }
 61 }
 62 
 63 void query(int l, int r, int step)
 64 {
 65     if (line[step].value != 0){
 66         if (!poster[line[step].value]){
 67             poster[line[step].value] = true;
 68             ans++;
 69         }
 70         return;
 71     }
 72     if (line[step].left == line[step].right)
 73         return;
 74     int mid = (line[step].left + line[step].right)>>1;
 75     if (r <= mid)
 76         query(l, r, step<<1);
 77     else if (l > mid)
 78         query(l, r, step<<1|1);
 79     else{
 80         query(l, mid, step<<1);
 81         query(mid+1, r, step<<1|1);
 82     }
 83 }
 84 
 85 int main()
 86 {
 87     int T;
 88     scanf("%d", &T);
 89     while(T--){
 90         memset(poster, 0, sizeof(poster));
 91         int n;
 92         int num = 0;
 93         scanf("%d", &n);
 94         for(int i = 1; i <= n; i++){
 95             int a, b;
 96             scanf("%d %d", &a, &b);
 97             sub[num++] = a;
 98             sub[num++] = b;
 99             in[i].a = a;
100             in[i].b = b;
101         }
102         
103         sort(sub, sub+num);
104         int size = unique(sub, sub+num) - sub; //删除重复数据并使用哈希表映射
105         for(int i = 0; i < size; i++)
106             hash[sub[i]] = i+1;
107             
108         buildt(1, size, 1); //离散后的值建树
109 
110         for(int i = 1; i <= n; i++)
111             update(hash[ in[i].a], hash[ in[i].b], i, 1); //用离散后的值更新
112         ans = 0;
113         query(1, size, 1);
114         printf("%d\n", ans);
115     }
116     return 0;
117 }