最后三个点一直WA，无论怎么改都是70分

#include<iostream>
#include<cmath>
#include<cstdio>
#define ll long long
using namespace std;
int s,v;
int h,m;
int a,b,c; 
int main()
{
	scanf("%d %d",&s,&v);
	a = s / v;
	if(s % v){
		a += 11;
	}else{
		a += 10;
	}
	if(a % 60){
		h = a / 60 + 1;
	}else{
		h = a / 60;
	}
	m = a % 60;
	m = 60 - m;
	if(h > 8){
		h = 24 - h;
	}else{
		h = 8 - h;
	}
	printf("%02d:%02d",h,m);
	return 0;
}