#include <bits/stdc++.h>   using namespace std;   const long long N = 1e5 + 5;   vector<long long> tim(N), pos(N), cur(N);      int main() {       long long T, n, act, start, des, dir, ans, startTime;       cin>>T;       for(long long t = 1; t <= T; ++t) {           tim[0] = pos[0] = start = des = act = ans = startTime = 0;           cin>>n;           for(long long i = 1; i <= n; ++i) {               cin>>tim[i]>>pos[i];               if(tim[i] >= act) {                   cur[i] = des;                   startTime = tim[i];                   act = tim[i] + abs(des - pos[i]);                   start = des;                   des = pos[i];               } else {                   dir = (start <= des) ? 1 : -1;                   cur[i] = start + dir * (tim[i] - startTime);               }           }           cur[n+1] = des;           for(long long i = 1; i <= n; ++i) {               if(min(cur[i],cur[i+1]) <= pos[i] && pos[i] <= max(cur[i],cur[i+1])) {                   ans += 1;               }           }           cout<<ans<<endl;       }       return 0;   }