求调

#include<bits/stdc++.h>
using namespace std;
int t,m;
long long sum=0;
struct sm{
	int a,b;
}s[100005];
bool cmp(sm c,sm d){
	return c.b/c.a>d.a/d.b;
}
int main()
{
	cin>>t>>m;
	for (int i=1;i<=m;i++){
		cin>>s[i].a>>s[i].b;
	}
	sort(s+1,s+1+m,cmp);
	int i=1;
	while (t){
		sum+=t/s[i].a*s[i].b;
		t=t%s[i].a;
		i++;
		if(i>m)break;
	}
	cout<<sum;
	return 0;
}

喃喃..尴尬