#include<iostream>
using namespace std;
int getTime()
{
    int h1,m1,s1,h2,m2,s2,d=0;
    int ss1=0;
    scanf("%d:%d:%d %d:%d:%d (+%d)",&h1,&m1,&s1,&h2,&m2,&s2,&d);
    ss1=d*24*60*60+h2*60*60+m2*60+s2-h1*60*60-m1*60-s1;
    return ss1;
}
int main()
{
    int t;
    cin>>t;
    for(int i=0;i<t;i++)
    {
        int t1=getTime();
        int t2=getTime();
        int tt=(t1+t2)/2;
        printf("%02d:%02d:%02d\n",tt/3600,tt/60%60,tt%60);
    }
}