Segmentation error

#include<stdio.h>
int main()
{
    int a;
    printf("Enter the order of a Month: ");
    scanf("%d", a);
    if(a==1)
    printf("31 days in january");
    else if(a==2)
    printf("28 days in february");
    else if(a==3)
    printf("31 days in march");
    else if(a==4)
    printf("30 days in april");
    else if(a==5)
    printf("31 days in may");
    else if(a==6)
    printf("30 days in june");
    else if(a==7)
    printf("31 days in july");
    else if(a==8)
    printf("31 days in august");
    else if(a==9)
    printf("30 days in september");
    else if(a==10)
    printf("31 days in october");
    else if(a==11)
    printf("30 days in november");
    else if(a==12)
    printf("31 days in december");
    else
    printf("Invaild value");
    return 0;
}