#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int inf = 0x3f3f3f3f;

int n,m,l[1010],r[1010],b[4010],dp[1010][4010];

int main(){
    for( int T ; scanf( "%d" , &T )==1 ; ){
        for( int cas=1 ; cas<=T ; cas++  ){
            scanf( "%d" , &n );
            m = 0;
            for( int i=1 ; i<=n ; i++ ){
                scanf( "%d%d" , &l[i] , &r[i] );
                b[++m] = l[i];
                b[++m] = r[i];
                if(l[i]<r[i]){
                    b[++m] = l[i]+1;
                    b[++m] = r[i]-1;
                }
            }
            sort( b+1 , b+m+1 );
            m = unique( b+1 , b+m+1 )-b-1;
            for( int i=1 ; i<=n ; i++ ){
                l[i] = lower_bound( b+1 , b+m+1 , l[i] )-b;
                r[i] = lower_bound( b+1 , b+m+1 , r[i] )-b;
            }
            for( int i=1 ; i<=m ; i++ ) dp[0][i] = 0;
            for( int i=1 ; i<=n ; i++ ){
                for( int j=1 ; j<=m ; j++ )
                    dp[i][j] = inf;
                for( int j=l[i] ; j<=r[i] ; j++ )
                    dp[i][j] = dp[i-1][j];
                for( int j=1 ; j<=m ; j++ ){
                    dp[i][l[i]] = min( dp[i][l[i]] , dp[i-1][j]+(abs(b[j]-b[l[i]])+1)/2 );
                    dp[i][r[i]] = min( dp[i][r[i]] , dp[i-1][j]+(abs(b[j]-b[r[i]])+1)/2 );
                    if( l[i]<r[i] ){
                        dp[i][l[i]+1] = min( dp[i][l[i]+1] , dp[i-1][j]+(abs(b[j]-b[l[i]+1])+1)/2 );
                        dp[i][r[i]-1] = min( dp[i][r[i]-1] , dp[i-1][j]+(abs(b[j]-b[r[i]-1])+1)/2 );
                    }
                }
                for( int j=1 ; j<=m ; j++ ){
                    dp[i][j] = min( dp[i][j] , dp[i][l[i]]+(abs(b[j]-b[l[i]])+1)/2 );
                    dp[i][j] = min( dp[i][j] , dp[i][r[i]]+(abs(b[j]-b[r[i]])+1)/2 );
                    if( l[i]<r[i] ){
                        dp[i][j] = min( dp[i][j] , dp[i][l[i]+1]+(abs(b[j]-b[l[i]+1])+1)/2 );
                        dp[i][j] = min( dp[i][j] , dp[i][r[i]-1]+(abs(b[j]-b[r[i]-1])+1)/2 );
                    }
                }
            }
            int ans = inf;
            for( int i=1 ; i<=m ; i++ )
                ans = min( ans , dp[n][i] );
            printf( "%d\n" , ans );
        }
    }
    return 0;
}