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

int main(){
    string t;
    cin >> t;
    int h = (t[0]-'0')*10+t[1]-'0';
    int m = (t[3]-'0')*10+t[4]-'0';
    string ans = "00:00";
    m += 5;
    if(m >= 60) h++;
    ans[3] += (m/10)%6;
    ans[4] += m%10;
    h %= 24;
    ans[0] += h/10;
    ans[1] += h%10;
    cout << ans << endl;
    return 0;
}