public static class Pair {

public int first;

public int second;

Pair(int first, int second) {

this.first = first;

this.second = second;

}

}

public static int n, m;

public static Pair[] mine = new Pair[3000];

public static Pair[] enemy = new Pair[3000];

public static int[] map = new int[1000002];

public static void main(String[] args) {

FastReader fr = new FastReader();

n = fr.nextInt();

m = fr.nextInt();

for (int i = 0; i < n; i++) {

int a = fr.nextInt();

int b = fr.nextInt();

mine[i] = new Pair(a, b);

}

for (int i = 0; i < m; i++) {

int c = fr.nextInt();

int d = fr.nextInt();

enemy[i] = new Pair(c, d);

}

// 위쪽으로 이동해야 하는 거리 계산

for (int i = 0; i < m; i++) {

Pair x = enemy[i];

for (int j = 0; j < n; j++) {

Pair y = mine[j];

if (x.first >= y.first) {

map[x.first - y.first] = Math.max(map[x.first - y.first], x.second - y.second + 1);

}

}

}

// 값 재조정

int maxValue = 0;

for (int i = 1000001; i >= 0; i--) {

maxValue = Math.max(maxValue, map[i]);

map[i] = maxValue;

}

// 최종 결과 출력

int result = 1000001;

for (int i = 0; i <= 1000001; i++) {

result = Math.min(result, i + map[i]);

}

System.out.println(result);

}

public static class FastReader {

BufferedReader br;

StringTokenizer st;

public FastReader() {

br = new BufferedReader(new InputStreamReader(System.in));

}

public FastReader(String s) throws FileNotFoundException {

br = new BufferedReader(new FileReader(new File(s)));

}

String next() {

while (st == null || !st.hasMoreElements()) {

try {

st = new StringTokenizer(br.readLine());

} catch (IOException e) {

e.printStackTrace();

}

}

return st.nextToken();

}

int nextInt() {

return Integer.parseInt(next());

}

long nextLong() {

return Long.parseLong(next());

}

double nextDouble() {

return Double.parseDouble(next());

}

String nextLine() {

String str = "";

try {

str = br.readLine();

} catch (IOException e) {

e.printStackTrace();

}

return str;

}

}

}