#include <bits/stdc++.h>
 using namespace std;
 int main(){
	int s,v,h=7,min=0;
	cin>>s>>v;
	min=(s+v-1)/v+10;
	while(min>60){
		min-=60;
		h--;
		if(h<0) h=23;
	}
	if(60-min>=10&&h<=10){
		cout<<"0"<<h<<":"<<60-min;
	}
	else if(60-min>=10&&h>=10){
		cout<<h<<":"<<60-min;
	}
	else if(60-min<=10&&h<=10){
		cout<<"0"<<h<<":0"<<60-min;
	}
	else if(60-min<=10&&h>=10){
		cout<<h<<":0"<<60-min;
	}
	return 0;
}