#include<bits/stdc++.h> using namespace std; #include<ext/pb_ds/assoc_container.hpp> #include<ext/pb_ds/tree_policy.hpp> using namespace __gnu_pbds; template <typename T> using ordset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>; /* less<T> can be changed to: 1. less_equal<T> 2. greater<T> ordered_set functions: 1. *(os.find_by_order(x)) -> return the value at position x (0 base) 2. os.order_of_key(x) -> return the number of elements less than x */ typedef long long ll; #define int ll #define endl '\n' #define pb push_back #define ff first #define ss second #define all(a) a.begin(),a.end() const int MOD=1000000007; #define gcd(a,b) __gcd(a,b) #define lcm(a,b) (a*(b/gcd(a,b))) #define fios(); ios_base::sync_with_stdio(0);cin.tie(0); #define fraction(x); cout.unsetf(ios::floatfield); cout.precision(x); cout.setf(ios::fixed,ios::floatfield); #define file(); freopen("input.txt","r",stdin);freopen("output.txt","w",stdout); void solve(){ int n; cin>>n; vector<pair<int,int>> a(n); for(int i=0;i<n;i++) cin>>a[i].ff>>a[i].ss; sort(all(a)); int preSum[n+1]={0}; //presum on a[i].ss for all i for(int i=0;i<n;i++) preSum[i+1]=preSum[i]+a[i].ss; ///for(int i=1;i<=n;i++) cout<<preSum[i]<<' '; //cout<<endl; int x[n]; for(int i=0;i<n;i++) x[i]=preSum[i+1]-a[i].ff; //for(int i=1;i<=n;i++) cout<<x[i-1]<<' '; //cout<<endl; int suffMax[n+1]; //suffmax on x[i] for all i for(int i=0;i<=n;i++) suffMax[i]=-1e15; for(int i=n;i>0;i--) suffMax[i]=max(suffMax[min(n,i+1)],x[i-1]); //for(int i=1;i<=n;i++) cout<<suffMax[i]<<' '; //cout<<endl; int ans=0; for(int i=0;i<n;i++){ ans=max(ans,a[i].ss); int tem=a[i].ff-preSum[i]; tem+=suffMax[i+1]; ans=max(ans,tem); //cout<<tem<<' '; } cout<<ans<<endl; return; } int32_t main(){ fios(); //file(); int t=1; //cin>>t; for(int tc=1;tc<=t;tc++){ //cout<<"Case "<<tc<<": "; solve(); } return 0; }