#include <bits/stdc++.h>

#define DEBUG(C) cerr << #C << " = " << C << endl

using namespace std;

const int MAX = 44;
int n;
long long a[MAX], b[MAX];
long long dp[MAX][2];
const long long inf = 1e18;

int main() {
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    scanf("%lld%lld", a + i, b + i);
  }
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < 2; j++) {
      dp[i][j] = inf;
    }
  }
  dp[0][0] = dp[0][1] = 0;
  for (int i = 0; i < n; i++) {
    dp[i + 1][0] = min(llabs(dp[i][0] + a[i]), llabs(dp[i][1] - a[i]));
    dp[i + 1][1] = min(llabs(dp[i][0] - b[i]), llabs(dp[i][1] + b[i]));
  }
  cout << min(llabs(dp[n][0]), llabs(dp[n][1])) << endl;
  return 0;
}