题解

#include<bits/stdc++.h>
using namespace std;
int a,b,c,d,e,f,n;
int main(){
    scanf("%d:%d:%d",&a,&b,&c);
    scanf("%d:%d:%d",&d,&e,&f);
    cin>>n;
    cout<<n*((d*3600+e*60+f)-(a*3600+b*60+c));
}