#include<iostream>
using namespace std;

int main(){
	int b;
	string zts,htz;//猪偷沙，猴偷猪
	cin>>zts;
	cin>>htz;
	cin>>b;
	long zs=0,hz=0;
	int a[5]={0,0,0,0,0};
	int t1=0,t2=0,t3=0;
	for(int i=0;i>=0;i++){
		if(zts[i]=':'){
			break;
		}
		else{
			a[i]=zts[i]-'0';
		}
		t1=i;
	}
	zs+=a[4]*36000000;
	zs+=a[3]*3600000;
	zs+=a[2]*360000;
	zs+=a[1]*36000;
	zs+=a[0]*3600;
	for(int i=t1;i>=t1;i++){
		if(zts[i]=':'){
			break;
		}
		else{
			a[i]=zts[i]-'0';
		}
		t2=i;
	}
	hz+=a[4]*600000;
	hz+=a[3]*60000;
	hz+=a[2]*6000;
	hz+=a[1]*600;
	hz+=a[0]*60;
	for(int i=t2;i>=t2;i++){
		if(zts[i]=':'){
			break;
		}
		else{
			a[i]=zts[i]-'0';
		}
		t1=i;
	}
	zs+=a[4]*10000;
	zs+=a[3]*1000;
	zs+=a[2]*100;
	zs+=a[1]*10;
	zs+=a[0]*1;
	////////////////////////////////////
	for(int i=0;i>=0;i++){
		if(zts[i]=':'){
			break;
		}
		else{
			a[i]=htz[i]-'0';
		}
		t1=i;
	}
	hz+=a[4]*36000000;
	hz+=a[3]*3600000;
	hz+=a[2]*360000;
	hz+=a[1]*36000;
	hz+=a[0]*3600;
	for(int i=t1;i>=t1;i++){
		if(zts[i]=':'){
			break;
		}
		else{
			a[i]=htz[i]-'0';
		}
		t2=i;
	}
	hz+=a[4]*600000;
	hz+=a[3]*60000;
	hz+=a[2]*6000;
	hz+=a[1]*600;
	hz+=a[0]*60;
	for(int i=t2;i>=t2;i++){
		if(zts[i]=':'){
			break;
		}
		else{
			a[i]=htz[i]-'0';
		}
		t1=i;
	}
	hz+=a[4]*10000;
	hz+=a[3]*1000;
	hz+=a[2]*100;
	hz+=a[1]*10;
	hz+=a[0]*1;
	t3=hz-zs;
	t3=t3*b;
	cout<<b;
	return 0;
}

不要说我傻，因为...