#include<bits/stdc++.h>
using namespace std;
int main()
{
    string a[12]={
        "MON TUE WED THU FRI SAT SUN\n          1   2   3   4   5 \n  6   7   8   9  10  11  12\n 13  14  15  16  17  18  19 \n 20  21  22  23  24  25  26 \n 27  28  29  30  31 \n",
        "MON TUE WED THU FRI SAT SUN\n                      1   2\n  3   4   5   6   7   8   9 \n 10  11  12  13  14  15  16 \n 17  18  19  20  21  22  23 \n 24  25  26  27  28 ",
        "MON TUE WED THU FRI SAT SUN\n                      1   2 \n  3   4   5   6   7   8   9 \n 10  11  12  13  14  15  16 \n 17  18  19  20  21  22  23 \n 24  25  26  27  28  29  30 \n 31 ",
        "MON TUE WED THU FRI SAT SUN\n      1   2   3   4   5   6 \n  7   8   9  10  11  12  13 \n 14  15  16  17  18  19  20 \n 21  22  23  24  25  26  27 \n 28  29  30 \n",
        "MON TUE WED THU FRI SAT SUN\n              1   2   3   4 \n  5   6   7   8   9  10  11 \n 12  13  14  15  16  17  18 \n 19  20  21  22  23  24  25 \n 26  27  28  29  30  31 ",
        "MON TUE WED THU FRI SAT SUN\n                      1   2 \n  3   4   5   6   7   8   9 \n 10  11  12  13  14  15  16 \n 17  18  19  20  21  22  23 \n 24  25  26  27  28  29  30 \n",
        "MON TUE WED THU FRI SAT SUN\n      1   2   3   4   5   6 \n  7   8   9  10  11  12  13 \n 14  15  16  17  18  19  20 \n 21  22  23  24  25  26  27 \n 28  29  30  31 \n",
        "MON TUE WED THU FRI SAT SUN\n                  1   2   3 \n  4   5   6   7   8   9  10 \n 11  12  13  14  15  16  17 \n 18  19  20  21  22  23  24 \n 25  26  27  28  29  30  31 \n",
        "MON TUE WED THU FRI SAT SUN\n  1   2   3   4   5   6   7 \n  8   9  10  11  12  13  14 \n 15  16  17  18  19  20  21 \n 22  23  24  25  26  27  28 \n 29  30 ",
        "MON TUE WED THU FRI SAT SUN\n          1   2   3   4   5 \n  6   7   8   9  10  11  12 \n 13  14  15  16  17  18  19 \n 20  21  22  23  24  25  26 \n 27  28  29  30  31 \n",
        "MON TUE WED THU FRI SAT SUN\n                      1   2 \n  3   4   5   6   7   8   9 \n 10  11  12  13  14  15  16 \n 17  18  19  20  21  22  23 \n 24  25  26  27  28  29  30 \n",
        "MON TUE WED THU FRI SAT SUN\n  1   2   3   4   5   6   7 \n  8   9  10  11  12  13  14 \n 15  16  17  18  19  20  21 \n 22  23  24  25  26  27  28 \n 29  30  31",
    };
    int n;
    cin>>n;
    cout<<a[n-1];
}

C++ :

#include <bits/stdc++.h>
using namespace std;

// 每个月的天数（默认平年）
int days_in_month[13] = {0,
    31, 28, 31, 30, 31, 30,
    31, 31, 30, 31, 30, 31
};

// 星期几的名字
string week[7] = {"MON","TUE","WED","THU","FRI","SAT","SUN"};

// 判断闰年
bool isLeap(int year) {
    return (year % 400 == 0) || (year % 4 == 0 && year % 100 != 0);
}

int main() {
    int m;
    cin >> m;

    int year = 2025;

    // 如果闰年，2月变成29天
    if (isLeap(year)) days_in_month[2] = 29;

    // 2025/1/1 是星期三 (WED)
    int first_day = 2; // 0=MON,1=TUE,2=WED,...

    // 累加前几个月的天数，得到m月1日的星期
    int offset = 0;
    for (int i = 1; i < m; i++) offset += days_in_month[i];
    int start_day = (first_day + offset) % 7;

    // 打印表头
    for (int i = 0; i < 7; i++) {
        cout << week[i];
        if (i < 6) cout << " ";
    }
    cout << "\n";

    // 打印空格（对齐）
    for (int i = 0; i < start_day; i++) cout << "    ";

    int days = days_in_month[m];
    for (int d = 1; d <= days; d++) {
       
        
        if(d < 10) cout << "  "; 
		else if(d <= 31) cout << " ";
		cout << d;
		if((start_day + d) % 7 == 0) cout << "\n";
		else cout << " ";
		
    }
    cout << "\n";

    return 0;
}