Problem D: 結構體：計算輸入日期是該年的第幾天

#include <stdio.h>
struct time{
int year;
int month;
int day;};
int main(void)
{
    struct time s1;
    int n;
    while(scanf("%d-%d-%d",&s1.year,&s1.month,&s1.day)!=EOF)
    {
        if(s1.year%4==0||s1.year%400==0)
        {
            if(s1.month==1)
                printf("%d\n",s1.day);
            if(s1.month==2)
                printf("%d\n",s1.day+31);
            if(s1.month==3)
                printf("%d\n",s1.day+31+29);
            if(s1.month==4)
                printf("%d\n",s1.day+31+29+31);
            if(s1.month==5)
                printf("%d\n",s1.day+31+29+31+30);
            if(s1.month==6)
                printf("%d\n",s1.day+31+29+31+30+31);
            if(s1.month==7)
                printf("%d\n",s1.day+31+29+31+30+31+30);
            if(s1.month==8)
                printf("%d\n",s1.day+31+29+31+30+31+30+31);
            if(s1.month==9)
                printf("%d\n",s1.day+31+29+31+30+31+30+31+31);
            if(s1.month==10)
                printf("%d\n",s1.day+31+29+31+30+31+30+31+31+30);
            if(s1.month==11)
                printf("%d\n",s1.day+31+29+31+30+31+30+31+31+30+31);
            if(s1.month==12)
                printf("%d\n",s1.day+31+29+31+30+31+30+31+31+30+31+30);
        }
        else
        {
            if(s1.month==1)
                printf("%d\n",s1.day);
            if(s1.month==2)
                printf("%d\n",s1.day+31);
            if(s1.month==3)
                printf("%d\n",s1.day+31+28);
            if(s1.month==4)
                printf("%d\n",s1.day+31+28+31);
            if(s1.month==5)
                printf("%d\n",s1.day+31+28+31+30);
            if(s1.month==6)
                printf("%d\n",s1.day+31+28+31+30+31);
            if(s1.month==7)
                printf("%d\n",s1.day+31+28+31+30+31+30);
            if(s1.month==8)
                printf("%d\n",s1.day+31+28+31+30+31+30+31);
            if(s1.month==9)
                printf("%d\n",s1.day+31+28+31+30+31+30+31+31);
            if(s1.month==10)
                printf("%d\n",s1.day+31+28+31+30+31+30+31+31+30);
            if(s1.month==11)
                printf("%d\n",s1.day+31+28+31+30+31+30+31+31+30+31);
            if(s1.month==12)
                printf("%d\n",s1.day+31+28+31+30+31+30+31+31+30+31+30);
        }
    }
    return 0; 
}