#include <bits/stdc++.h>
using namespace std;
int main(){
	int s,v,t=10;
	cin>>s>>v;
	if(v<s) t=s%v==0?t+s/v:t+s/v+1;
	if(t<=480){
		int ts=t/60;
		int tf=t-ts*60;
		if(60-tf>=10)cout<<"0"<<7-ts<<":"<<60-tf;
		else cout<<"0"<<7-ts<<":"<<"0"<<60-tf;
	}
	else if(t>480&&t<=1080){
		t=t-480;
		int ts=t/60;
		int tf=t-ts*60;
		if(60-tf>=10)cout<<23-ts<<":"<<60-tf;
		else cout<<23-ts<<":"<<"0"<<60-tf;
		}
	else{
		t=t-1080;
		int ts=t/60;
		int tf=t-ts*60;
		if(60-tf>=10)cout<<"0"<<9-ts<<":"<<60-tf;
		else cout<<"0"<<9-ts<<":0"<<60-tf;
	}
}

求救思密达