#include<iostream>
#include<algorithm>
#include<vector>
#include<bits/stdc++.h>
using namespace std;
struct node{
    double price;
    int yield;
}farm[2000000];
bool cmp(int a,int b){
    return a<b;
}
int main(){
    int a,n,ans_y=0,ans_p=0;
    cin>>a,n;
    for(int i=1;i<=n;i++){
        cin>>farm[i].price;
        cin>>farm[i].yield;
    }
    std::soft(farm,farm+n,cmp);
    for(int i=1;i<=n;i++){
        if(ans_y>=a){
            break;
        }
        ans_y+=farm[i].yield;
        ans_p+=farm[i].price;
    }
    cout<<ans_p;
    return 0;
}
    
    

评测状态 Compile Error