简单模拟即可

#include <iostream>
#include <cstring>
#include <cstdio>
#include <algorithm>
using namespace std;
int day,month;
int days[13] = {0,31,28,31,30,31,30,31,31,30,31,30,31};
int leap(int year)
{
    if(year % 4 == 0 && year % 100 != 0 || year % 400 == 0) return 1;
    return 0;
}
int main()
{
    int year,num;
    cin >> year >> num;
    days[2] += leap(year);
    int cnt = 1;
    while(num)
    {
        if(num <= days[cnt])
        {
            month = cnt;
            day = num;
            break;
        }
        else
        {
            num -= days[cnt];
            cnt++;
        }
    }
    cout << month << endl << day << endl;
    return 0;
}