#include <iostream>
using namespace std;
int main(){
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    long long h, m, hans, mans; cin >> h >> m;
    hans=(330+((h*60+m-330)%16?((h*60+m-330)/16+1)*16:h*60+m-330))%1440/60;
    mans=(330+((h*60+m-330)%16?((h*60+m-330)/16+1)*16:h*60+m-330))%1440%60;
    cout << hans << (mans<10?":0":":") << mans;
    return 0;
}