#include <cassert>
#include <cmath>
#include <algorithm>
#include <iostream>
#include <iomanip>
#include <climits>
#include <map>
#include <queue>
#include <set>
#include <cstring>
#include <vector>

using namespace std;
typedef long long ll;

int main() {
  int N;
  cin >> N;
  vector<int> A(N);
  vector<int> B(N);

  for (int i = 0; i < N; ++i) {
    cin >> A[i] >> B[i];
  }

  vector<vector<vector<int>>> dp(N + 1, vector<vector<int>>(2, vector<int>(N * 1001, INT_MAX)));
  dp[0][0][0] = 0;
  dp[0][1][0] = 0;

  for (int i = 0; i < N; ++i) {
    int a = A[i];
    int b = B[i];

    for (int j = 0; j < 2; ++j) {
      for (int k = 1000 * (i + 1); k >= 0; --k) {
        if (dp[i][j][k] == INT_MAX) continue;
        int a_time, b_time, n_a_time, n_b_time;

        if (j == 0) {
          a_time = k;
          b_time = dp[i][j][k];
        } else {
          a_time = dp[i][j][k];
          b_time = k;
        }

        n_a_time = a_time + a;
        n_b_time = b_time + b;

        dp[i + 1][0][n_a_time] = min(dp[i + 1][0][n_a_time], b_time);
        dp[i + 1][0][a_time] = min(dp[i + 1][0][a_time], n_b_time);
        dp[i + 1][1][n_b_time] = min(dp[i + 1][1][n_b_time], a_time);
        dp[i + 1][1][b_time] = min(dp[i + 1][1][b_time], n_a_time);
      }
    }
  }

  int ans = INT_MAX;

  for (int t = 0; t < N * 1001; ++t) {
    if (dp[N][0][t] != INT_MAX) ans = min(ans, max(t, dp[N][0][t]));
    if (dp[N][1][t] != INT_MAX) ans = min(ans, max(t, dp[N][1][t]));
  }

  cout << ans << endl;

  return 0;
}