第五个点WA掉，求助……

#include<iostream>
#include<cstring>
using namespace std;
bool jz[1100];
int hs[1100];
int n,k,f,x,y,ans,qs=0,waste=0;
int main()
{
    memset(jz,0,sizeof(jz));
    memset(hs,0,sizeof(hs));
    cin>>n>>k>>f;
    for(int i=1;i<=f;++i)
    {
    cin>>x>>y;
    jz[x]=1;
    hs[x]+=y;
    }
    while(n!=0)
    {
        qs++;
        if(jz[qs]==1)
        {
            if(k-((waste+1)%k)>=hs[qs])
            {
                n--;
                waste=waste+hs[qs]+1;
            }
            else
            {
                n--;
                waste=waste+(k-(waste%k))+hs[qs]+1;
            }
        }
        else
        {
            n--;
            waste++;
        }
    }
    if(waste%k==0)
    ans=waste/k;
    else
    ans=waste/k+1;
    cout<<ans;
    return 0;
}