sf("%d",&n);int cnt = 0,len = 1;for(i=1;i<=n;i++)//记录头尾
        {sf("%d %d",&s1[i],&s2[i]);a[++cnt] = s1[i];a[++cnt] = s2[i];}sort(a+1,a+1+cnt);for(i=2;i<=cnt;i++)//去重
        {if(a[i]!=a[i-1]) a[++len] = a[i];}for(i=len;i>1;i--)//添加中间值
        {if(a[i]-a[i-1]>1) a[++len] = a[i]-1;}sort(a+1,a+1+len);for(i=1;i<=n;i++){int l = BSearch(1,len,s1[i]);int r = BSearch(1,len,s2[i]);update(i,l,r,1,len,1);}

#include <iostream>
#include <string>
#include <cstring>
#include <cstdlib>
#include <cstdio>
#include <cmath>
#include <algorithm>
#include <stack>
#include <queue>
#include <cctype>
#include <vector>
#include <iterator>
#include <set>
#include <map>
#include <sstream>
using namespace std;#define mem(a,b) memset(a,b,sizeof(a))
#define pf printf
#define sf scanf
#define spf sprintf
#define pb push_back
#define debug printf("!\n")
#define MAXN 10000 + 5
#define MAX(a,b) a>b?a:b
#define blank pf("\n")
#define LL long long
#define ALL(x) x.begin(),x.end()
#define INS(x) inserter(x,x.begin())
#define pqueue priority_queue
#define INF 0x3f3f3f3fint n,m;int a[MAXN<<4],col[MAXN<<4],ans;int s1[MAXN],s2[MAXN];bool hh[MAXN];void PushDown(int rt)
{if(col[rt] != -1){col[rt<<1] = col[rt<<1|1] = col[rt];col[rt] = -1;}
}void update(int val,int L,int R,int l,int r,int rt)
{if(L <= l && r <= R){col[rt] = val;return;}PushDown(rt);int mid = (l + r)>>1;if (L <= mid){update(val,L,R,l,mid,rt<<1);}if(R > mid){update(val,L,R,mid+1,r,rt<<1|1);}
}void query(int l,int r,int rt)
{if(l==r){if(!hh[col[rt]]){ans++;hh[col[rt]] = true;}return;}PushDown(rt);int mid = (l + r)>>1;query(l,mid,rt<<1);query(mid+1,r,rt<<1|1);
}int BSearch(int lo, int hi, int v)
{int mid;while (lo <= hi){mid = (lo + hi) >> 1;if (a[mid] == v) return mid;else if (a[mid] > v)  hi = mid - 1;else lo = mid + 1;}return -1;
}int main()
{int t,i,kase=1;sf("%d",&t);while(t--){mem(col,-1);mem(a,0);mem(hh,false);sf("%d",&n);int cnt = 0,len = 1;for(i=1;i<=n;i++)//????
        {sf("%d %d",&s1[i],&s2[i]);a[++cnt] = s1[i];a[++cnt] = s2[i];}sort(a+1,a+1+cnt);for(i=2;i<=cnt;i++)//??
        {if(a[i]!=a[i-1]) a[++len] = a[i];}for(i=len;i>1;i--)//?????
        {if(a[i]-a[i-1]>1) a[++len] = a[i]-1;}sort(a+1,a+1+len);for(i=1;i<=n;i++){int l = BSearch(1,len,s1[i]);int r = BSearch(1,len,s2[i]);update(i,l,r,1,len,1);}ans = 0;query(1,len,1);pf("%d\n",ans);}return 0;
}