프로그래머스: 멀쩡한 사각형

public long solution(long w,long h) {
    long big = w > h ? w : h;
    long small = w > h ? h : w;

    while (small != 0) {
        long r = big % small;
        big = small;
        small = r;
    }

    return (w * h) - (w + h - big);
}

assertEquals(80, test.solution(8, 12));
assertEquals(12, test.solution(5, 4));
assertEquals(40, test.solution(10, 5));
assertEquals(352, test.solution(17, 23));
assertEquals(30467460, test.solution(3, 15233730));