#include<bits/stdc++.h>
using namespace std;

#define FOR(i, a, b) for(int i = a; i < b; ++i)
#define REP(i, n) FOR(i, 0, n)
#define _ << " " <<
#define sz(x) ((int) x.size())
#define pb(x) push_back(x)
#define TRACE(x) cerr << #x << " = " << x << endl

typedef long long ll;
typedef pair<ll, ll> point;

const int MAXN = 5e5 + 5, off = 1 << 20, inf = 1e9 + 5;

int n;
multiset <ll> S;
point a[MAXN];

int main(){
  ios_base::sync_with_stdio(false); cin.tie(0);

  cin >> n;

  ll sol = 0;
  REP(i, n)
    cin >> a[i].second >> a[i].first;

  for(int i = n - 1; i >= 0; --i){
    if(a[i].second == 1)
      S.insert(a[i].first);
    else{
      ll x = 0;
      if(sz(S)) { auto it = S.end(); it --; x = *it; }
      ll profit = x - a[i].first;
      if(profit > 0){
        sol += profit;
        S.erase(S.find(x));
        S.insert(x - profit);
      }
    }
  }
  cout << sol;
}