题目链接：耍杂技的牛

#include <iostream>
#include <algorithm>

using namespace std;

typedef pair<int, int> PII;

const int N = 50010;

int n;
PII cow[N];

int main()
{
    cin >> n;
    for(int i = 0; i < n; i ++)
    {
        int w, s;
        cin >> w >> s;
        cow[i] = {w + s, w};
    }
    
    sort(cow, cow + n);
    
    // sum: 每头牛上面的重量之和
    int res = -2e9, sum = 0;
    for(int i = 0; i < n; i ++)
    {
        int w = cow[i].second, s = cow[i].first - w;
        res = max(res, sum - s);
        sum += w;
    }
    
    cout << res << endl;
    
    return 0;
}