代码如下

#include<cstdio>
#include<algorithm>
using namespace std;
struct yao{
  int j;
  int t;
  double jt;
};
bool cmp(yao a,yao b){
  return a.jt>b.jt;
}
int main(){
  int n,x,sum=0;
  yao k[1000];
  scanf("%d%d",&x,&n);
  for(int i=0;i<n;i++){
    scanf("%d%d",&k[i].t,&k[i].j);
    k[i].jt=(double)k[i].j/k[i].t;
    
  }
  sort(k,k+n,cmp);
  for(int i=0;i<n;i++){
    if(k[i].t<=x){
      sum+=k[i].j;
      x-=k[i].t;
    }
  }
  printf("%d",sum);
  return 0;
}