#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cassert>
#include <cmath>
#include <algorithm>
#include <string>
#include <vector>
#include <queue>
#include <list>
#include <set>
#include <map>

using namespace std;

#define eprintf(...) fprintf(stderr, __VA_ARGS__)
#define pb push_back
#define mp make_pair
#define sz(x) ((int)(x).size())
#define TASKNAME "restack"
#ifdef _WIN32
#define LLD "%I64d"
#elif linux
#define LLD "%lld"
#else
#error Invalid OS...
#endif

typedef long long ll;
typedef vector<ll> vll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<bool> vb;
typedef vector<vb> vvb;
typedef pair<int, int> pii;

int n;
vi as;

ll calc(ll tn1) {
  ll ans = abs(tn1);
  ll sum = tn1;
  for (int i = 0; i + 1 < n; i++) {
    sum += as[i];
    ans += abs(sum);
  }
  return ans;
}

int main() {
  freopen(TASKNAME ".in", "r", stdin);
  freopen(TASKNAME ".out", "w", stdout);

  while (scanf("%d", &n) >= 1) {
    as = vi(n);
    for (int i = 0; i < n; i++) {
      int x, y;
      scanf("%d%d", &x, &y);
      as[i] = x - y;
    }

    int L = -3e8, R = 3e8;
    while (L + 2 < R) {
      int M1 = (L + R) / 2;
      int M2 = M1 + 1;

      ll v1 = calc(M1), v2 = calc(M2);
      if (v1 <= v2) R = M1;
      else L = M2;
    }

    ll bans = 9e18;
    for (int i = L; i <= R; i++)
      bans = min(bans, calc(i));
    printf(LLD"\n", bans);
  }
  return 0;
}