#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
int main() {
    int n;
    cin>>n;
    ll k, a, b, c, d, dist = 0, pares = 0, distPosi = 0;
    while(n>0){
        pares = 0;
        distPosi = 0;
        dist = 0;
        cin>>a>>b>>c>>d;
        for(int i = a;i<=b;i++){
            dist = k-(i+c);
            if(dist==0){
                pares+=d-c;
            }else if(dist<0){
                pares+=d-c+1;
            }else{
                pares+=d-dist-c;
            }
        }
        cout<<pares<<"\n";
      n--;
    }
}