#include<bits/stdc++.h>
using namespace std;
int main(){
	int a,b,n=1910,m;
	cin >> a >> b;
	if(a%b!=0){
		a/=b;
		a++;
	}
	n-=a;
	if(n>=1440){
		n-=1440;
	}
	m=n;
	n/=60;
	m%=60;
	printf("%02d:%02d",n,m);
}

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