agitatie

#include <bits/stdc++.h>
#define ABS(x) ((x) >= 0 ? (x) : -(x))

using namespace std;

ifstream fin ("agitatie.in");
ofstream fout ("agitatie.out");

int N, k, mx, j;
vector < int > a, v;
vector < int > dp[2];

int main () {
  fin >> N;
  a = v = vector < int > (N);
  for (int i = 0; i < N; i ++) {
    fin >> a[i] >> v[i];
    mx = max (mx, a[i]);
  }
  dp[0] = dp[1] = vector < int > (mx + 2);
  for (int i = N - 1; i >= 0; i --)
    for (j = mx, k = 1 - k, dp[k][j + 1] = INT_MAX; j >= 0; j --)
      dp[k][j] = min (dp[k][j + 1], ABS (a[i] + v[i] * j) + dp[1 - k][j]);
  fout << dp[k][0];
  fin.close();
  fout.close();
  return 0;
}