이 문제좀 풀어주실 수 있나요

#include <stdio.h> 
 
int main(void) 
{ 
        int month, days; 
         
        printf("달을 입력하시오: "); 
        scanf("%d", &month); 
 
 
        switch(month) 
        { 
                case 2: 
                        days = 28; 
                        break; 
                case 4: 
                case 6: 
                case 9: 
                case 11: 
                        days = 30; 
                        break; 
                default: 
                        days = 31; 
                        break; 
        } 
        printf("%d월의 일수는 %d입니다.\n", month, days); 
        return 0; 
}