#include<bits/stdc++.h>
#define INF 0x3f3f3f3f
#define mod 1000000007
using namespace std;
inline int gcd(int a, int b) { return b ? gcd(b, a % b) : a; }
typedef long long LL;
typedef pair<int, int>PII;
const int N = 100100;
int n;
LL tim[N];
LL pos[N];
void solve() {
  cin >> n;
  for (int i = 0; i < n; ++i) {
    cin >> tim[i] >> pos[i];
  }
  tim[n] = 1e10;
  LL net = 0; //下一次停止的时间
  LL st = 0, ed = 0; //一次指令的起点和终点
  LL las = 0; //上一次接收到命令的时间
  LL res = 0;
  for (int i = 0; i < n; ++i) {
    if (tim[i] >= net) {
      net = tim[i] + abs(pos[i] - ed);
      st = ed, ed = pos[i];
      las = i;
      if (net <= tim[i + 1])
        res++;
    }
    else {
      if (st >= ed) {
        int y = st - (tim[i] - tim[las]);
        int x = max(ed, st - (tim[i + 1] - tim[las]));
        if (pos[i] >= x && pos[i] <= y)res++;
      }
      else {
        int x = st + (tim[i] - tim[las]);
        int y = min(ed, st + tim[i + 1] - tim[las]);
        if (pos[i] >= x && pos[i] <= y)res++;
      }
    }
  }
  cout << res << endl;
}
int main() {
  int t; cin >> t;
  while (t--)
    solve();
  return 0;
}