#include <cstdio>

using namespace std;

int main() {
    int dis, v;
    scanf("%d%d", &dis, &v);
    
    int time = (dis / v) + 1 + 10;
    
    int end = 480;
    int beg = end - time;
    
    if (beg < 0) beg += 24 * 60;
    
    printf("%02d:%02d\n", beg / 60, beg % 60);
    
    return 0;
}