class Solution {
public:
    
    int monthdays(int year, int month){
        if (month==2){
            if ((year%4==0&&year%100!=0)||year%400==0){
                return 29;
            }
            else{
                return 28;
            }
        }
        else if (month==1||month==3||month==5||month==7||month==8||month==10||month==12){
            return 31;
        }
        else{
            return 30;
        }
    }
    
    int yeardays(int year){
        int sum = 0;
        for(int i=1;i<=12;i++){
            sum += monthdays(year, i);
        }
        return sum;
    }
    
    // year1(2019.1.31)>=year2(2019.1.1)
    // year1(2019.2.1)>=year2(2019.1.1)
    // year1(2020.2.1)>=year2(2020.1.1)
    int distance(int year, int month, int day, int minyear, int minmmonth, int minday){
        int sum = 0;
        for(int ii=minyear;ii<year;ii++){
            sum += yeardays(ii);
        }
        for(int ii=minmmonth;ii<month;ii++){
            sum += monthdays(year, ii);
        }
        sum += day-minday;
        return sum;
    }
    
    
    int daysBetweenDates(string date1, string date2) {
        int year1 = atoi(date1.substr(0,4).c_str());
        int month1 = atoi(date1.substr(5,2).c_str());
        int day1 = atoi(date1.substr(8,2).c_str());
        int year2 = atoi(date2.substr(0,4).c_str());
        int month2 = atoi(date2.substr(5,2).c_str());
        int day2 = atoi(date2.substr(8,2).c_str());
        
        int minyear = year1<year2?year1:year2;
        int minmonth = 1;
        int minday = 1;
        int dis1 = distance(year1, month1, day1, minyear, minmonth, minday);
        int dis2 = distance(year2, month2, day2, minyear, minmonth, minday);
        return abs(dis1-dis2);
        
    }
};