#include<bits/stdc++.h>
const int maxn = 1010;
int t,n;
int f[maxn][maxn << 2];
int a[maxn],b[maxn];
std::vector<int> v;
inline int calc(int x,int y){
    if(x > y) std::swap(x,y);
    return v[y] - v[x] + 1 >> 1;
}
inline void down(int & x,int y){if(x > y)x = y;}
inline int find(int x){ return std::lower_bound(v.begin(),v.end(),x) - v.begin(); }
int main(){
    std::ios::sync_with_stdio(false),std::cin.tie(0);
    std::cin >> t;
    while(t--){
        std::cin >> n; v.clear();
        for(int i=1;i<=n;++i){
            std::cin >> a[i] >> b[i];
            v.push_back(a[i]); v.push_back(b[i]); 
            if(a[i] != b[i]) v.push_back(a[i] + 1), v.push_back(b[i] - 1);     
        }
        std::sort(v.begin(),v.end()); v.erase(std::unique(v.begin(),v.end()),v.end());
        for(int i=0;i<v.size();++i) f[0][i] = 0;
        for(int i=1;i<=n;++i){
            for(int j=0;j<v.size();++j)
                if(a[i] <= v[j] && v[j] <= b[i]) f[i][j] = f[i-1][j];
                else f[i][j] = 2e9;
            int x = find(a[i]);
            for(int j=0;j<v.size();++j) down(f[i][x],f[i-1][j] + calc(j,x));
            x = find(b[i]);
            for(int j=0;j<v.size();++j) down(f[i][x],f[i-1][j] + calc(j,x));
            if(a[i] != b[i]){
                int x = find(a[i] + 1);
                for(int j=0;j<v.size();++j) down(f[i][x],f[i-1][j] + calc(j,x));
                x = find(b[i] - 1);
                for(int j=0;j<v.size();++j) down(f[i][x],f[i-1][j] + calc(j,x));
            }
        }
        std::cout << * std::min_element(f[n],f[n] + v.size()) << '\n';
    }
}