#include <iostream>
using namespace std;

int main()
{
	long long int a1, a2, a3;
	long long int b1, b2, b3;
	char ch;
	long long int steal;
	cin >> a1 >> ch >> a2 >> ch >> a3;
	cin >> b1 >> ch >> b2 >> ch >> b3;
	cin >> steal;
	long long a = (a2 - a1)*3600 + (b2 - a2)*60 + b3 - a3;
	cout << a*steal << endl;

	system("pause");
	return 0;
}

求助，是哪里出错了