// process.stdin.resume();
// process.stdin.setEncoding('utf8');
// Here your code !


// inputに入力データ全体が入る
function Main(input) {
	// 1行目がinput[0], 2行目がinput[1], …に入る
	input = input.split(" ");
	let firstDay = input[0];
	let lastDay = input[1];
	const firstEventDay = 23;
	const lastEventDay = 25;
	
	if (lastDay < firstEventDay) {
	    console.log(3);
	    return;
	} else if (lastEventDay < firstDay) {
	    console.log(3);
	    return;
	}
	if (firstDay < firstEventDay && lastEventDay < lastDay) {
	    console.log(0);
	    return;
	}
	if (lastDay <= lastEventDay) {
	    console.log(lastEventDay - lastDay);
	    return;
	}
	console.log(lastEventDay - firstDay);
}
//*この行以降は編集しないでください（標準入出力から一度に読み込み、Mainを呼び出します）
Main(require("fs").readFileSync("/dev/stdin", "utf8"));