Given a certain day a year, converting it into the first few days of the year and output

#include <stdio.h>
int main ( )
{
    int y,m,d,day=0;
    int a[2][12]=
    {
        {31,28,31,30,31,30,31,31,30,31,30,31},
        {31,29,31,30,31,30,31,31,30,31,30,31},
        
    };
    
    
    scanf("%d%d%d",&y,&m,&d);
    //除一月份以外都要进行的判断
    for (int i = 1; i < m; i++) {
        if ((y%100!=0&&y%4==0)||y%400==0) {
            day+=a[1][i-1];
        }
        else day+=a[0][i-1];
    }
    printf("%d",day+d);
}