#include <iostream>

 #include <set>

 #include <cstring>

 using namespace std;

 //快速幂运算

 #define MAX  59084709587505

 #define LL  long long

 int Time(){

     char line[]={};

     cin.getline(line,);//getline读到换行

     int n1,m1,s1,n2,m2,s2,h=;

     if(strlen(line)==){

         sscanf(line,"%d:%d:%d %d:%d:%d",&n1,&m1,&s1,&n2,&m2,&s2);

     }

     else{

         sscanf(line,"%d:%d:%d %d:%d:%d (+%d)",&n1,&m1,&s1,&n2,&m2,&s2,&h);

     }

     int time=h**+n2*+m2*+s2-(n1*+m1*+s1);//全化成秒方便计算

     return time;

 }

 int main(){

     int T;

     (cin>>T).get();//把行尾的空格吃掉，要不会被getline 当成时间来读

     for (int i = ; i <= T; ++i) {

         int time1=Time();

         int time2=Time();

         int ans=(time2+time2)/;

         printf("%02d:%02d:%02d\n",ans/,ans/%,ans%);//秒化小时化分钟

     }

     }