public class Solution { int mon[] = new int[]{0,31,28,31,30,31,30,31,31,30,31,30,31}; boolean isYear(int year){ if((year%4==0&&year%100!=0)||year%400==0)return true; return false; } boolean check(int y1, int m1, int d1, int y2, int m2, int d2){ if(y2...