#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
#define MP(a,b) make_pair(a,b)
int main() {
	ios::sync_with_stdio ( false );
	int s, v;
	scanf ( "%d%d", &s, &v );
	int t = ceil ( 1.0 * s / v ) + 10;
	int zero = 60 * ( 24 + 8 ) - t;
	int h = ( zero / 60 ) % 24;
	int m = zero % 60;
	printf ( "%02d:%02d\n", h, m );
	return 0;
}