//Normal

#define _GLIBCXX_DEBUG
#define ll long long
#include <bits/stdc++.h>
using namespace std;
using Graph = vector<vector<int>>;

void print(auto a){
  cout << a;
}

void prints(auto a){
  cout << a << " ";
}

void prints(){
  cout << " ";
}

void printl(auto a){
  cout << a << endl;
}

void printl(){
  cout << endl;
}

void fix(int n){
  cout << fixed << setprecision(n);
}

int main(){
  string T; cin >> T;
  
  int t1 = (int)T.size();
  int t2 = (int)T.find(":");
  
  int H = stoi(T.substr(0, t2));
  int M = stoi(T.substr(t2+1, t1));
  
  if(M >= 55){
    H = (H+1)%24;
    M -= 55;
  }else{
    M += 5;
  }
  
  printf("%02d:%02d\n", H, M);
  
  return 0;
}