其实很简单

#include<iostream>
using namespace std;
int main()
{
    int k,m,n,i,a,b,s;
    cin>>k>>m>>n;
    for (i=1; i<=m; i++)
    {
        cin>>a>>b;
        if (a==0 || b*(k/a)>=n) {cout<<i<<" "; s=1;}
    }
    if (s==0) cout<<"-1";
    return 0;
}