#include <iostream>
#include <cstdio>
#include <algorithm>
#include <string>
#include <cstring>
#include <cctype>
#include <cmath>
#include <stack>
#include <queue>
#include <vector>
#include <set>
#include <map>
#include <list>
#include <stdio.h>
#include <string.h>
#include <cstdlib>
#include <math.h>
#include <bitset>
#include <iterator>
#include <iomanip>
#include <sstream>
#define INF 2000000000
using namespace std;
int dx[4]={1,0,-1,0},dy[4]={0,1,0,-1};
#define sym cout<<"---------"<<endl;
#define ll long long
#define PL pair<long long, long long>
#define P pair<int,int>
#define mk make_pair
#define en endl
#define WHITE 0
#define BLACK 2
#define GRAY 1
#define RE return 0
#define int ll


signed main(){
  int h,m;
  char ch;
  cin>>h>>ch>>m;
  if(m>=55){
    h++;
    if(h==24) h=0;
    m=m+5-60;
  }else m+=5;
  if(h>=10) cout<<h<<':';
  else cout<<0<<h<<':';
  if(m>=10) cout<<m<<en;
  else cout<<0<<m<<en;
}