#pragma GCC optimize("Ofast")
#pragma GCC optimize("inline")
#include<bits/stdc++.h>
using namespace std;
const int inf=1.5e9;

int T, n, m, p[5030], f[5030];

int li[5010], ri[5010];

void fuck(int l,int r){
  for (int i=1;i<=m;++i)
    if (p[i]>=l&&p[i]<=r){
    }else{
      f[i]=inf;
    }
}

inline void Umn(int &x,int y){
  x=min(x,y);
}

void fix(int l,int r){
  l=lower_bound(p+1,p+m+1,l)-p;
  r=lower_bound(p+1,p+m+1,r)-p;
  static int pre[2];
  pre[0]=pre[1]=0;
  for (int i=l;i<=m;++i){
    if (pre[0]){
      if (p[i]%2==0){
    Umn(f[i],(p[i]-p[pre[0]])/2+f[pre[0]]);
      }else{
    Umn(f[i],(p[i]-p[pre[0]])/2+1+f[pre[0]]);
      }
    }
    if (pre[1]){
      if (p[i]%2==0){
    Umn(f[i],(p[i]-p[pre[1]])/2+1+f[pre[1]]);
      }else{
    Umn(f[i],(p[i]-p[pre[1]])/2+f[pre[1]]);
      }
    }
    pre[(p[i]%2+2)%2]=i;
  }
  pre[0]=pre[1]=0;
  for (int i=r;i>=1;--i){
    if (pre[0]){
      if (p[i]%2==0){
    Umn(f[i],(-p[i]+p[pre[0]])/2+f[pre[0]]);
      }else{
    Umn(f[i],(-p[i]+p[pre[0]])/2+1+f[pre[0]]);
      }
    }
    if (pre[1]){
      if (p[i]%2==0){
    Umn(f[i],(-p[i]+p[pre[1]])/2+1+f[pre[1]]);
      }else{
    Umn(f[i],(-p[i]+p[pre[1]])/2+f[pre[1]]);
      }
    }
    pre[(p[i]%2+2)%2]=i;
  }
}

int main(){
  for (cin>>T;T--;){
    cin>>n; m=0;
    for (int i=1;i<=n;++i){
      scanf("%d%d",&li[i],&ri[i]);
      //p[++m]=li[i]-1;
      p[++m]=li[i];
      p[++m]=li[i]+1;
      p[++m]=ri[i]-1;
      p[++m]=ri[i];
      //p[++m]=ri[i]+1;
    }
    sort(p+1,p+m+1);
    m=unique(p+1,p+m+1)-p-1;
    memset(f,0,sizeof f);
    for (int i=1;i<=n;++i){
      fuck(li[i],ri[i]);
      //for (int j=1;j<=m;++j) printf(" %d",f[j]); puts("");
      fix(li[i],ri[i]);
      //for (int j=1;j<=m;++j) printf(" %d",f[j]); puts("");
    }
    printf("%d\n",*min_element(f+1,f+m+1));
  }
}