#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, h, m;
  int mo, md, ho, hd;
  string t;
  cin >> t;
  n = t.size();
  m = (t[n - 2] - '0') * 10 + t[n - 1] - '0';
  h = (t[n - 5] - '0') * 10 + t[n - 4] - '0';
  for (;;) {
    m = (m + 1) % 60;
    if (m == 0) {
      h = (h + 1) % 24;
    }
    ho = h % 10;
    hd = h / 10;
    mo = m % 10;
    md = m / 10;
    if (hd == mo && ho == md) {
      cout << hd << ho << ":" << md << mo << endl;
      break;
    }
  }
}
