#include <bits/stdc++.h>
using namespace std;
int a,b,c,d,e,f,g;
char h;
int main()
{
	cin>>a>>h>>b>>h>>c>>h>>d>>h>>e>>h>>f>>h>>g;
	cout<<g*((d-a)*3600+(e-b)*60+f-c);
	return 0;
}