#include <bits/stdc++.h>
using namespace std;
int main() {
  int hh, mm, a, n;
  char z, x, c, v, b;
  cin >> z >> x >> c >> v >> b >> a;
  hh = ((int)z - '0') * 10 + ((int)x - '0');
  mm = ((int)v - '0') * 10 + ((int)b - '0');
  n = hh * 60 + mm;
  n = n + a;
  n = n % 1440;
  hh = n / 60;
  mm = n - hh * 60;
  if (hh >= 10)
    cout << hh;
  else
    cout << "0" << hh;
  cout << ":";
  if (mm >= 10)
    cout << mm;
  else
    cout << "0" << mm;
}
