Problem ChuanSongMen P5690
Why I'm code is eighty points?
I don't know why.
It's WA on #8,#10,but I don't know why.
Do you want's to help me to accepted this problem?
Thanks!

This is my code (language is C++):

#include<bits/stdc++.h>
#define int long long
using namespace std;
int a,b,z;
signed main(){
	scanf("%lld-%lld",&a,&b);
	if(a<1)z++;
	if(a>12){
		z++;
		a%=10;
		if(a==0)a=10;
	}
	if(a==2&&(b<0||b>28))z++;
	if((a==1||a==3||a==5||a==7||a==8||a==10||a==12)&&(b<0||b>31))z++;
	if((a==2||a==4||a==6||a==9||a==11)&&(b<0||b>30))z++;
	if(b<1)z++;
	cout<<z;
	return 0;
}

Thanks your help!!!