#include <stdio.h>
int main(){
    int month;
    scanf("%d",&month);
    
    
    if(month <= 1 || month >= 12){
        printf("Invalid input");
        return 0;
    }
    
    switch (month);
    
    case 1: printf(31);break;
    case 2: printf(28);break;
    case 3: printf(31);break;
    case 4: printf(30);break;
    case 5: printf(31);break;
    default: printf();break;
}