import java.util.HashSet;
import java.util.Arrays;
import java.util.List;

class MyClass {

  public static void main(String[] args) {
    List<Integer> leapYears = Arrays.asList(1804, 1808, 1812, 1816, 1820, 1824, 1828, 1832, 1836, 1840, 1844, 1848, 1852, 1856, 1860, 1864, 1868, 1872, 1876, 1880, 1884, 1888, 1892, 1896, 1904, 1908, 1912, 1916, 1920, 1924, 1928, 1932, 1936, 1940, 1944, 1948, 1952, 1956, 1960, 1964, 1968, 1972, 1976, 1980, 1984, 1988, 1992, 1996, 2000, 2004, 2008, 2012, 2016, 2020, 2024, 2028, 2032, 2036, 2040, 2044, 2048, 2052, 2056, 2060, 2064, 2068, 2072, 2076, 2080, 2084, 2088, 2092, 2096, 2104, 2108, 2112, 2116, 2120, 2124, 2128, 2132, 2136, 2140, 2144, 2148, 2152, 2156, 2160, 2164, 2168, 2172, 2176, 2180, 2184, 2188, 2192, 2196, 2204, 2208, 2212, 2216, 2220, 2224, 2228, 2232, 2236, 2240, 2244, 2248, 2252, 2256, 2260, 2264, 2268, 2272, 2276, 2280, 2284, 2288, 2292, 2296, 2304, 2308, 2312, 2316, 2320, 2324, 2328, 2332, 2336, 2340, 2344, 2348, 2352, 2356, 2360, 2364, 2368, 2372, 2376, 2380, 2384, 2388, 2392, 2396, 2400);
    for(Integer year = 1804; year < 2400; year++) {
      for(Integer month : Arrays.asList(1,3,5,7,8,10,12)) {
        assert daysInMonth(month, year) == 31;
      }
      for(Integer month : Arrays.asList(4,6,9,11)) {
        assert daysInMonth(month, year) == 30;
      }
      if(leapYears.contains(year)) {
        assert daysInMonth(2, year) == 29;
      }
      else {
        assert daysInMonth(2, year) == 28;
      }
    }
  }

  public static int daysInMonth(int m, int y) {
    HashSet<Integer> monthsWith31Days = new HashSet<Integer>(Arrays.asList(1,3,5,7,8,10,12));
    HashSet<Integer> monthsWith30Days = new HashSet<Integer>(Arrays.asList(4,6,9,11));

    if(monthsWith31Days.contains(m)) {
      return 31;
    } else if(monthsWith30Days.contains(m)) {
      return 30;
    }
    else if(isLeapYear(y)) {
      return 29;
    }
    else {
      return 28;
    }
  }

  public static boolean isLeapYear(int year) {
    if (year % 4 != 0) {
      return false;
    } else if (year % 400 == 0) {
      return true;
    } else if (year % 100 == 0) {
      return false;
    } else {
      return true;
    }
  }
}