#include <iostream>
#include <istream>
#include <sstream>
#include <fstream>
#include <string>
#include <vector>
#include <deque>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <algorithm>
#include <functional>
#include <utility>
#include <bitset>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <cstdio>

using namespace std;

#define REP(i, n) for(int i = 0; i < n;i++)

typedef long long ll;

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	/*
	int n, m;
	int a[110];
	cin >> n >> m;
	for (int i = 0; i < n; i++) cin >> a[i];
	for (int i = 0; i < m; i++) {
		for (int j = 0; j < n; j++) {
			if (j % i > (j + 1) % i) swap(a[i], a[i + 1]);
		}
	}
	cout << a[0];
	for (int i = 0; i < n; i++) cout << a[i] << endl;
	*/
	int h, m;
	char c;
	cin >> h >> c >> m;
	if ((m + 5) >= 60) {
		h = (h + 1) % 24;
	}
	m = (m + 5) % 60;
	printf("%02d:%02d\n", h, m);
}