`C`

`" "`

#include <stdio.h>

int main() {
    int t;

    printf("Nhap thang: ");
    scanf("%d", &t);

    if (t == 1 || t == 3 || t == 5 || t == 7 || t == 8 || t == 10 || t == 12) 
        printf("Thang %d co 31 ngay", t);
    else if (t == 4 || t == 6 || t == 9 || t == 11)
        printf("Thang %d co 30 ngay", t);
    else if (t == 2) 
        printf("Thang 2 co the co 28 hoac 29 ngay");
    else 
        printf("Thang khong hop le");
    
    return 0;
}