求问做法正确性（附民间75ptscode）

/*why i even try*/
#include<bits/stdc++.h>
#define int unsigned long long
using namespace std;
const int mxn=1e5+10;
int mnsum=1e9+10,n,m,ans=0;
struct cy{
	int a,b,sum;
}c[mxn];
bool bi2(cy x,cy y){
	return x.a<y.a;
}
signed main(){
	ios::sync_with_stdio(0);
//	freopen("candy7.in","r",stdin);
	cin>>n>>m;
	for(int i=1;i<=n;i++) cin>>c[i].a>>c[i].b,c[i].sum=c[i].a+c[i].b,mnsum=min(mnsum,c[i].sum);
	ans+=(m/mnsum)*2,m%=mnsum;
	sort(c+1,c+1+n,bi2);
	for(int i=1;i<=n;i++){
		if(m<c[i].a) break;
		else ans++,m-=c[i].a;
	}
	cout<<ans;
	return 0;
}