#include <bits/stdc++.h>
using namespace std;
int main() {
  string s, s5;
  cin >> s;
  int c = 0;
  string s3 = "", s4 = "";
  s3 += s[0];
  s3 += s[1];
  s4 += s[3];
  s4 += s[4];
  int a = atoi(s3.c_str());
  int b = atoi(s4.c_str());
  while (1) {
    if (b == 59) {
      if (a == 23)
        a = 0, s3[0] = '0', s3[1] = '0';
      else {
        a++;
        stringstream ss;
        ss << a;
        s5 = ss.str();
        if (a < 10) {
          s3 = "0";
          s3 += s5;
        } else
          s3 = s5;
      }
      b = 0;
      s4[0] = '0', s4[1] = '0';
    } else {
      b++;
      stringstream ss;
      ss << b;
      s5 = ss.str();
      if (b < 10) {
        s4 = "0";
        s4 += s5;
      } else
        s4 = s5;
    }
    c++;
    if (s3[0] == s4[1] && s3[1] == s4[0] && c > 0) break;
  }
  cout << s3 << ":" << s4 << endl;
}
