#include<bits/stdc++.h>
#define fi first
#define se second
#define pb push_back
#define SZ(x) ((int)x.size())
#define L(i,u) for (register int i=head[u]; i; i=nxt[i])
#define rep(i,a,b) for (register int i=(a); i<=(b); i++)
#define per(i,a,b) for (register int i=(a); i>=(b); i--)
using namespace std;
typedef long long ll;
typedef unsigned int ui;
typedef pair<int,int> Pii;
typedef vector<int> Vi;
template<class T> inline void read(T &x){
    x=0; char c=getchar(); int f=1;
    while (!isdigit(c)) {if (c=='-') f=-1; c=getchar();}
    while (isdigit(c)) {x=x*10+c-'0'; c=getchar();} x*=f;
}
template<class T> inline void umin(T &x, T y){x=x<y?x:y;}
template<class T> inline void umax(T &x, T y){x=x>y?x:y;}
inline ui R() {
    static ui seed=416;
    return seed^=seed>>5,seed^=seed<<17,seed^=seed>>13;
}
const int N = 4040,inf=0x3f3f3f3f;
int n,l[N],r[N],dp[1020][N],s[N],len;
int calc(int i, int j){if(i>j)swap(i,j);return (s[j]-s[i]+1)/2;}
int main() {
    int T;read(T);while(T--){
        read(n);rep(i,1,n)read(l[i]),read(r[i]);
        len=0;
        rep(i,1,n){
            s[++len]=l[i];s[++len]=l[i]+1;
            s[++len]=r[i];s[++len]=r[i]-1;
        }
        sort(s+1,s+len+1);len=unique(s+1,s+len+1)-s-1;
        rep(i,1,n)l[i]=lower_bound(s+1,s+len+1,l[i])-s;
        rep(i,1,n)r[i]=lower_bound(s+1,s+len+1,r[i])-s;
        memset(dp,inf,sizeof(dp));rep(i,1,len)dp[0][i]=0;
        rep(i,0,n-1)rep(j,1,len){
            if(j<l[i+1]){
                umin(dp[i+1][l[i+1]],dp[i][j]+calc(j,l[i+1]));
                if(l[i+1]+1<=r[i+1])umin(dp[i+1][l[i+1]+1],dp[i][j]+calc(j,l[i+1]+1));
            }
            else if(j>r[i+1]){
                umin(dp[i+1][r[i+1]],dp[i][j]+calc(j,r[i+1]));
                if(l[i+1]<=r[i+1]-1)umin(dp[i+1][r[i+1]-1],dp[i][j]+calc(j,r[i+1]-1));
            }
            else umin(dp[i+1][j],dp[i][j]);
        }
        int res=inf;rep(i,1,len)umin(res,dp[n][i]);printf("%d\n",res);
    }
    return 0;
}