#include <iostream>
#include <algorithm>
#include <cstring>
#include <string>
#include <vector>
#include <queue>
#include <deque>
#include <cmath>

#define AS(a) (sizeof(a)/sizeof(a[0]))
using namespace std;
long long int MOD = 1000000007;
long long int INF = 1000000007;


int main() {
  string T;
  cin >> T;
  string hh = T.substr(0,2);



  int h = std::stoi(T.substr(0,2));
  int m = std::stoi(T.substr(3,5));

  if(m >= 55) {
    m = (m + 5) % 60;
    h++;
  } else {
    m = (m + 5);
  }
  if(h >= 24) {
    h = h % 24;
  }
  printf("%02d:%02d\n",h,m);



}