#include <bits/stdc++.h>
using namespace std;
const int N = 1000000;
array<int, 2> pos[N];
vector<int> seats[N];
int n, m;
struct segtree {
int mini, count, lazy;
} mini[4 * N];
void apply(int u, int x) {
mini[u].lazy += x, mini[u].mini += x;
}
void push(int u) {
if (mini[u].lazy != 0) {
apply(2 * u, mini[u].lazy);
apply(2 * u + 1, mini[u].lazy);
mini[u].lazy = 0;
}
}
void pull(int u) {
mini[u].mini = min(mini[2 * u].mini, mini[2 * u + 1].mini);
mini[u].count = 0;
if (mini[2 * u].mini == mini[u].mini) {
mini[u].count += mini[2 * u].count;
}
if (mini[2 * u + 1].mini == mini[u].mini) {
mini[u].count += mini[2 * u + 1].count;
}
}
void build(int u, int l, int r) {
mini[u].count = r - l + 1;
if (l < r) {
int m = (l + r) / 2;
build(2 * u, l, m);
build(2 * u + 1, m + 1, r);
}
}
void update(int u, int a, int b, int x, int l, int r) {
if (a > b || b < l || r < a) {
return;
} else if (a <= l && r <= b) {
apply(u, x);
} else {
push(u);
int m = (l + r) / 2;
update(2 * u, a, b, x, l, m);
update(2 * u + 1, a, b, x, m + 1, r);
pull(u);
}
}
void update(int i, int j, int x) {
vector<int> in;
for (auto ki : {-1, 0}) {
for (auto kj : {-1, 0}) {
if (0 <= i + ki && i + ki < n && 0 <= j + kj && j + kj < m) {
in.push_back(seats[i + ki][j + kj]);
} else {
in.push_back(n * m);
}
}
}
sort(in.begin(), in.end());
update(1, in[0], in[1] - 1, x, 0, n * m - 1);
update(1, in[2], in[3] - 1, 4 * x, 0, n * m - 1);
}
void give_initial_chart(int n, int m, vector<int> r, vector<int> c) {
::n = n, ::m = m;
fill(seats, seats + n, vector<int>(m));
for (int i = 0; i < n * m; ++i) {
seats[r[i]][c[i]] = i;
pos[i] = {r[i], c[i]};
}
build(1, 0, n * m - 1);
for (int i = 0; i <= n; ++i) {
for (int j = 0; j <= m; ++j) {
update(i, j, 1);
}
}
}
int swap_seats(int a, int b) {
vector<array<int, 2>> cells;
for (auto k : {a, b}) {
auto [i, j] = pos[k];
for (auto ki : {0, 1}) {
for (auto kj : {0, 1}) {
cells.push_back({i + ki, j + kj});
}
}
}
sort(cells.begin(), cells.end());
cells.erase(unique(cells.begin(), cells.end()), cells.end());
for (auto [i, j] : cells) {
update(i, j, -1);
}
swap(seats[pos[a][0]][pos[a][1]], seats[pos[b][0]][pos[b][1]]);
swap(pos[a], pos[b]);
for (auto [i, j] : cells) {
update(i, j, 1);
}
return mini[1].count;
}
