import std.conv, std.functional, std.range, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.bitmanip, std.complex, std.container, std.math, std.mathspecial, std.numeric, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }

string COLOR(string s = "") { return "\x1b[" ~ s ~ "m"; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; }
int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); }
int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); }




void main() {
  try {
    for (; ; ) {
      const numCases = readInt;
      foreach (caseId; 0 .. numCases) {
        const N = readInt;
        const M = readLong;
        auto L = new long[N]; foreach (i; 0 .. N) L[i] = readLong;
        auto R = new long[N]; foreach (i; 0 .. N) R[i] = readLong;
        
        if (L.sum <= M && M <= R.sum) {
          long lo = L.minElement;
          long hi = R.maxElement + 1;
          for (; lo + 1 < hi; ) {
            const mid = (lo + hi) / 2;
            long sum;
            foreach (i; 0 .. N) {
              sum += min(max(mid, L[i]), R[i]);
            }
            ((sum <= M) ? lo : hi) = mid;
          }
          long ans;
          {
            long sum;
            foreach (i; 0 .. N) {
              const t = min(max(lo, L[i]), R[i]);
              sum += t;
              ans += t * (t - 1) / 2;
            }
            ans += (M - sum) * lo;
          }
          ans = 1L * M * (M - 1) / 2 - ans;
          writeln(ans);
        } else {
          writeln(-1);
        }
      }
    }
  } catch (EOFException e) {
  }
}