编辑代码

#include <iostream>
#include <algorithm>
using namespace std;

int m,n,sum;
struct node
{
    int p,a;
}w[114];

bool cmp(node n1,node n2)
{
    return n1.p < n2.p;
}

int main() {
    cin>>m>>n;
    
    for(int i = 1;i <= n;i++)
    {
        cin>>w[i].p>>w[i].a;
    }
    sort(w + 1,w + n + 1,cmp);

    for(int i = 1;i <= n;i++)
    {
        if(m > w[i].p * w[i].a)
        {
            sum += w[i].a;
            m -= w[i].p * w[i].a;
        }
        else
        {
            sum += m / w[i].p;
            break;
        }
    }

    cout<<sum;

	return 0;
}