using namespace std;
int a,b,c;
int a1,b1,c1;
int main(){
	cin>>a>>b>>c>>a1>>b1>>c1;
	if(a>a1 || a==a1&&b>b1 || a==a1&&b==b1&&c>c1){
		cout<<-1;
	}
	else if(a1>a && b>b1 || a1>a && b==b1 && c>c1){
		cout<<a1-a-1;
	}
	else{
		cout<<a1-a;
	}
	return 0;
}