#include <iostream>
using namespace std;
int main(){
	string pig;
	string monkey;
	cin >>pig;
	cin >>monkey;
	int n,computer;
	cin >>n;
	int time_2;
	int time=0;
	time=(pig[0]-'0')*3600*10+(pig[1]-'0')*3600+(pig[3]-'0')*60*10+(pig[4]-'0')*60+(pig[6]-'0')*10+(pig[7]-'0');
	time_2=(monkey[0]-'0')*3600*10+(monkey[1]-'0')*3600+(monkey[3]-'0')*60*10+(monkey[4]-'0')*60+(monkey[6]-'0')*10+(monkey[7]-'0');
	computer=(time_2-time)*n;
	cout <<computer;
	return 0;
}

那里写的有点长，麻烦dalao放到自己的编译器里看，谢谢！