#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

int main() {
    int n, m;
    cin >> n >> m;

    vector<int> x(n), y(m);
    for (int i = 0; i < n; ++i) {
        cin >> x[i];
    }
    for (int i = 0; i < m; ++i) {
        cin >> y[i];
    }

    // 对两个数组进行排序
    sort(x.begin(), x.end());
    sort(y.begin(), y.end());

    int minDistance = INT_MAX;
    int i = 0, j = 0;

    // 使用双指针遍历两个数组
    while (i < n && j < m) {
        minDistance = min(minDistance, abs(x[i] - y[j]));
        if (x[i] < y[j]) {
            ++i;
        } else {
            ++j;
        }
    }

    cout << minDistance << endl;
    return 0;
}