#include<bits/stdc++.h>
using namespace std;
int main()
{
	int sj=10,s,u,y;
	cin>>s>>u;
	sj=sj+s/u; 
	y=480-sj;
	if(sj>=480)
	y=1440+y;
	sj=y/60;
	y=y%60;
	if(y>9&&sj>9)
	cout<<sj<<":"<<y-1;
	else if(y<9&&sj>9)	
	cout<<sj<<":"<<0<<y-1;
	else if(y<9&&sj<9)
	cout<<0<<sj<<":"<<0<<y-1;
	else
	cout<<0<<sj<<":"<<y-1;
	return 0;
 }