log = console.log;
var stdin = require("fs").readFileSync("/dev/stdin", "UTF-8");
var lines = stdin
  .split(" ")
  .filter(v => v !== "")
  .map(Number);

var W = lines[0];
var H = lines[1];
var x = lines[2];
var y = lines[3];

var isCenter;
if(x === W/2 && y === H/2){
  isCenter = 1
} else {
  isCenter = 0
}
log(W * H /2,isCenter)