#include<bits/stdc++.h>
using namespace std;
int n;
long long get_time = 0,ans= 0
struct times{
	int hour,minutes,second;
}a[3];
int main(){
	scanf("%d:%d:%d\n%d:%d:%d\n%d",&a[0].hour,&a[0].minutes,&a[0].second,&a[1].hour,&a[1].minutes,&a[1].second,&n);
	ans = 3600*(a[1].hour-a[0].hour)*n+60*(a[1].minutes-a[0].minutes)*n+(a[1].second-a[0].second)*n;
	printf("%ld",ans);
	return 0;
}