#include<iostream>
using namespace std;
int main(){
	int a,b,c,d,e,f,n;
	char m;
	cin>>a>>m>>b>>m>>c;
	cin>>d>>m>>e>>m>>f;
	cin>>n;
	int g=d-a;
	int h=e-b;
	int i=f-c;
	int j=3600*g*n+60*h*n+i*n;
	cout<<j;
	return 0;
}