#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
using namespace std;
bool sortbysec(const pair<char, int> &a, const pair<char, int> &b) {
  return (a.second < b.second);
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  string ip, hh, mm;
  cin >> ip;
  hh = ip.substr(0, 2);
  string hr = hh;
  reverse(hr.begin(), hr.end());
  mm = ip.substr(3, 4);
  if (hh == "23" && (stoi(mm) >= stoi(hr)))
    cout << "00:00";
  else if (hh == "06" || hh == "07" || hh == "08" || hh == "09")
    cout << "10:01";
  else if (hh == "15" && stoi(mm) >= 51 || hh == "16" || hh == "17" ||
           hh == "18" || hh == "19")
    cout << "20:02";
  else if (stoi(mm) < stoi(hr))
    cout << hh << ":" << hr;
  else {
    int x = (stoi(hh) + 1) % 10 * 10 + stoi(hh) / 10;
    int y = stoi(hh) + 1;
    if (y >= 10)
      cout << y << ":" << x;
    else
      cout << "0" << y << ":" << x;
  }
  return 0;
}
