#include<bits/stdc++.h>
using namespace std;

int main()
{
    int t,m;
    cin>>t>>m;
    int tf[m],moneyf[m],ts[m],moneys[m];
    double xjbf[m],xjbs[m] = {0};
    for(int i = 0;i<m;i++)
    {
        cin>>tf[i]>>moneyf[i];
    }
    for(int i = 0;i<m;i++)
    {
        xjbf[i] = moneyf[i]/tf[i];
    }
    for(int i = m;i>0;i--)
    {
        for(int j = 0;j<m;j++)
        {
            if(xjbf[j]>xjbs[i])
            {
                xjbs[i] = xjbf[j];
                ts[i] = tf[j];
                moneys[i] = moneyf[j];
                xjbf[j] = 0;
            }
        }
    }
    int allt = 0,allm = 0,i = 0;
    do
    {
        if(ts[0]>allt)
        {
            break;
        }
        allt+=ts[i];
        allm+=moneys[i];
        i++;
    }
    while(allt+ts[i]<=t);
    cout<<allm<<endl;
    return 0;
}

全部报WA，求帮助，thanks