#include <bits/stdc++.h>   using namespace std;   const int maxn = 1e7 + 5;   int l, r, x, y;   char c;   int main() {     cin >> l >> c >> r;     cin >> x >> c >> y;     l = l * 60 + r;     x = x * 60 + y;     l = l - x;     if (l < 0) {       l += 24 * 60;     }     printf( %02d:%02d n , l / 60, l % 60);     return 0;   }   