#include <bits/stdc++.h>
using namespace std;
int main()
{
	int s,v;cin >> s >> v;
	int h = s/v,rsd = s%v,t = -10;
	if(rsd>0){
		t-=1;//单位是分钟 
	}
	t-=h;
	int ans = 8*60+t;
	if(ans>=0){
		int xiaoshi = ans/60,mint = ans%60;
		printf("%0.2d:%0.2d",xiaoshi,mint);
	}
	else {
		int ans2 = 24*60+ans;
		int xiaoshi = ans2/60,mint = ans2%60;
		printf("%0.2d:%0.2d",xiaoshi,mint);
	}
	return 0;
}