#include <iostream>

using namespace std;

const int INF = 1 << 25;

int main() {
    int N;
    cin >> N;

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

    int ok = 3000, ng = 0;
    while (ok - ng > 1) {
        int mid = (ok + ng) / 2;

        int dp[1 << N];
        fill(dp, dp + (1 << N), INF);
        dp[0] = 0;

        for (int b = 1; b < (1 << N); ++b) {
            for (int i = 0; i < N; ++i) {
                if ((b >> i & 1) == 0) continue;

                int r = dp[b ^ (1 << i)];
                if (b == (1 << i) || r + A[i] <= mid) {
                    dp[b] = min(dp[b], B[i] - A[i]);
                }
            }
        }

        if (dp[(1 << N) - 1] < INF) {
            ok = mid;
        } else {
            ng = mid;
        }
    }

    cout << ok << endl;
    return 0;
}