#ifdef t9unkubj
#include"debug.cpp"
//#include"template_no_debug.h"
#else
#define dbg(...) 199958
#endif
#undef _GLIBCXX_DEBUG
#pragma GCC optimize("O3")
using namespace std;
#include<bits/stdc++.h>
using ll=long long;
using ull=unsigned long long;
template<class T>using vc=vector<T>;
template<class T>using vvc=vc<vc<T>>;
#define rep(i,n) for(ll i=0;i<(ll)(n);i++)
#define REP(i,j,n) for(ll i=(j);i<(ll)(n);i++)
#define DREP(i,n,m) for(ll i=(n);i>=(m);i--)
#define drep(i,n) for(ll i=((n)-1);i>=0;i--)
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
template<class T,class F>
bool chmin(T &x, F y){
if(x>y){
x=y;
return true;
}
return false;
}
template<class T, class F>
bool chmax(T &x, F y){
if(x<y){
x=y;
return true;
}
return false;
}
double pass_time=0;
void solve(){
int n;
cin>>n;
vc<pair<int,int>>h(n);
rep(i,n)cin>>h[i].first>>h[i].second;
sort(all(h));
multiset<int>st{0};
rep(i,n){
st.insert(h[i].first);
auto it1=st.upper_bound(h[i].first-h[i].second);
auto it2=prev(it1);
int inc=*it1-(h[i].first-h[i].second);
int val=*it2;
if(it2!=st.begin())st.erase(it2);
st.insert(val+inc);
st.erase(it1);
}
vc<ll>cnt(st.size());
int I=st.size()-1;
for(auto itr=st.begin();next(itr)!=st.end();itr++){
cnt[I--]=*next(itr)-*itr;
}
dbg(cnt);
ll ans=0;
rep(i,cnt.size()){
ans+=i*(i-1)/2*cnt[i];
}
cout<<ans<<"\n";
}
signed main(){
cin.tie(0)->sync_with_stdio(0);
pass_time=clock();
int t=1;
//cin>>t;
while(t--)solve();
pass_time=clock()-pass_time;
dbg(pass_time/CLOCKS_PER_SEC);
}
