#include <bits/stdc++.h>   using namespace std;   int main() {     int t;     cin >> t;     while (t--) {       long long int str, in, ex, z;       cin >> str >> in >> ex;       if (str + ex - in <= 0) {         cout << 0 << endl;       } else {         if (ex + in < str) {           z = ex + 1;         } else {           z = ex;         }         if ((str + ex - in) % 2 == 0) {           cout << min(((str + ex - in) / 2), z) << endl;         } else {           cout << min((((str + ex - in) / 2) + 1), z) << endl;         }       }     }     return 0;   }   