#include <iostream>
#include <iomanip>
using namespace std;

int output(int h, int m){
	if(h <= 9){
		cout << 0 << h << ":";
	}else{
		cout << h << ":";
	}
	if(m <= 9){
		cout << 0 << m << endl;
	}else{
		cout << m << endl;
	}
}
 
int main(){
	string T;
	cin >> T;
	int h = (T[0] - '0') * 10 + (T[1] - '0');
	int m = (T[3] - '0') * 10 + (T[4] - '0');
	if(m >= 55){
		if(h == 23){
			output(0, m - 55);
		}else{
			output(h + 1, m - 55);
		}
	}else{
		output(h, m + 5);
	}
}