#include <stdio.h>
#include <stdlib.h>

int max(int a, int b) {
    return (a > b) ? a : b;
}

int getLastMoment(int n, int* left, int leftSize, int* right, int rightSize) {
    int maxTime = 0;
    
    // Left-moving ants: time to fall = current position
    for (int i = 0; i < leftSize; i++) {
        maxTime = max(maxTime, left[i]);
    }
    
    // Right-moving ants: time to fall = distance to right end
    for (int i = 0; i < rightSize; i++) {
        maxTime = max(maxTime, n - right[i]);
    }
    
    return maxTime;
}

int main() {
    int n;
    scanf("%d", &n);
    
    int left[1000], right[1000];
    int leftSize = 0, rightSize = 0;
    
    // Read left array size and elements
    scanf("%d", &leftSize);
    for (int i = 0; i < leftSize; i++) {
        scanf("%d", &left[i]);
    }
    
    // Read right array size and elements
    scanf("%d", &rightSize);
    for (int i = 0; i < rightSize; i++) {
        scanf("%d", &right[i]);
    }
    
    printf("%d\n", getLastMoment(n, left, leftSize, right, rightSize));
    return 0;
}