#include <bits/stdc++.h>   using namespace std;   int main() {     int h1, m1, h2, m2, s1, s2, h, m;     scanf( %d:%d , &h1, &m1);     scanf( %d:%d , &h2, &m2);     s1 = h1 * 60 + m1;     s2 = h2 * 60 + m2;     m = (s1 + s2) / 2;     h = m / 60;     m = m % 60;     printf( %02d:%02d n , h, m);     return 0;   }   