package main

import (
	"bufio"
	"fmt"
	"os"
)

func main() {
	r := bufio.NewReader(os.Stdin)
	w := bufio.NewWriter(os.Stdout)
	defer w.Flush()

	var t int
	fmt.Fscan(r, &t)
	for i := 0; i < t; i++ {
		var n, m, row, c int64
		fmt.Fscan(r, &n, &m, &row, &c)
		fmt.Fprintln(w, (m-c)+(n-row)*(2*m-1))
	}
}