import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
public class joi2019_ho_t4 {
static final long INF = 1000000000000000000L;
static int totalCoins;
static int[] coinX;
static int[] coinY;
static int[] auxX;
static int[] auxY;
public static void main(String[] args) throws IOException {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
int N = parseInt(br.readLine().trim());
totalCoins = 2 * N;
coinX = new int[totalCoins + 1];
coinY = new int[totalCoins + 1];
for (int i = 1; i <= totalCoins; i++) {
String[] parts = mySplit(br.readLine());
coinX[i] = parseInt(parts[0]);
coinY[i] = parseInt(parts[1]);
}
auxX = new int[totalCoins + 1];
auxY = new int[totalCoins + 1];
mergeSort(1, totalCoins);
long[] dp = new long[N + 1];
for (int j = 0; j <= N; j++) dp[j] = INF;
dp[0] = 0;
for (int i = 1; i <= totalCoins; i++) {
long[] ndp = new long[N + 1];
for (int j = 0; j <= N; j++) ndp[j] = INF;
for (int j = 0; j <= Math.min(i - 1, N); j++) {
if (dp[j] == INF) continue;
int cntRow2 = (i - 1) - j;
if (j < N) {
int targetX1 = j + 1;
long cost1 = abs(coinX[i] - targetX1) + abs(coinY[i] - 1);
if (dp[j] + cost1 < ndp[j + 1]) ndp[j + 1] = dp[j] + cost1;
}
if (cntRow2 < N) {
int targetX2 = cntRow2 + 1;
long cost2 = abs(coinX[i] - targetX2) + abs(coinY[i] - 2);
if (dp[j] + cost2 < ndp[j]) ndp[j] = dp[j] + cost2;
}
}
dp = ndp;
}
PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));
out.println(dp[N]);
out.flush();
}
static void mergeSort(int l, int r) {
if(l >= r) return;
int m = (l + r) / 2;
mergeSort(l, m);
mergeSort(m+1, r);
int i = l, j = m+1, k = l;
while(i <= m && j <= r) {
if(coinX[i] < coinX[j] || (coinX[i] == coinX[j] && coinY[i] <= coinY[j])) {
auxX[k] = coinX[i];
auxY[k] = coinY[i];
i++;
} else {
auxX[k] = coinX[j];
auxY[k] = coinY[j];
j++;
}
k++;
}
while(i <= m) { auxX[k] = coinX[i]; auxY[k] = coinY[i]; i++; k++; }
while(j <= r) { auxX[k] = coinX[j]; auxY[k] = coinY[j]; j++; k++; }
for (i = l; i <= r; i++) {
coinX[i] = auxX[i];
coinY[i] = auxY[i];
}
}
static int abs(int a) { return a < 0 ? -a : a; }
static String[] mySplit(String s) {
int len = s.length(), cnt = 0;
boolean inToken = false;
for (int i = 0; i < len; i++) {
if (!isSpace(s.charAt(i))) { if (!inToken) { cnt++; inToken = true; } }
else { inToken = false; }
}
String[] tokens = new String[cnt];
int index = 0;
StringBuilder sb = new StringBuilder();
inToken = false;
for (int i = 0; i < len; i++) {
char c = s.charAt(i);
if (!isSpace(c)) { sb.append(c); inToken = true; }
else { if (inToken) { tokens[index++] = sb.toString(); sb.setLength(0); inToken = false; } }
}
if (inToken) tokens[index++] = sb.toString();
return tokens;
}
static boolean isSpace(char c) { return c == ' ' || c == '\t' || c == '\n' || c == '\r'; }
static int parseInt(String s) {
int i = 0, n = s.length(), num = 0, sign = 1;
if(n == 0)return 0;
char c = s.charAt(0);
if(c == '-') { sign = -1; i++; } else if(c == '+') { i++; }
for(; i < n; i++){
num = num * 10 + (s.charAt(i) - '0');
}
return sign * num;
}
}
