#include <bits/stdc++.h>
using namespace std;
int H, W;
vector<int> R, C, diff, elem;
class SegmentTree {
private:
struct Node {
int pre_mn, pre_cnt, sum;
Node() {
pre_mn = pre_cnt = sum = 0;
}
void merge(Node l, Node r) {
pre_mn = l.pre_mn;
pre_cnt = l.pre_cnt;
if (l.sum + r.pre_mn == pre_mn) {
pre_cnt += r.pre_cnt;
}
if (l.sum + r.pre_mn < pre_mn) {
pre_mn = l.sum + r.pre_mn;
pre_cnt = r.pre_cnt;
}
sum = l.sum + r.sum;
}
};
vector<Node> seg;
const int LO, HI;
void build(int l, int r, int node, const vector<int> &arr) {
if (l == r) {
seg[node].pre_mn = seg[node].sum = arr[l];
seg[node].pre_cnt = 1;
return;
}
const int mid = l + (r - l) / 2;
build(l, mid, 2 * node + 1, arr);
build(mid + 1, r, 2 * node + 2, arr);
seg[node].merge(seg[2 * node + 1], seg[2 * node + 2]);
}
void modify(int where, int delta, int l, int r, int node) {
if (l > where || r < where) return;
if (l == where && r == where) {
seg[node].pre_mn = seg[node].sum = delta;
seg[node].pre_cnt = 1;
return;
}
const int mid = l + (r - l) / 2;
modify(where, delta, l, mid, 2 * node + 1);
modify(where, delta, mid + 1, r, 2 * node + 2);
seg[node].merge(seg[2 * node + 1], seg[2 * node + 2]);
}
public:
SegmentTree(const vector<int> &arr) : LO(0), HI((int)arr.size() - 1){
seg.clear();
seg.resize(4 * arr.size());
build(LO, HI, 0, arr);
}
int get_ans() {
return seg[0].pre_cnt;
}
void modify(int where, int delta) {
modify(where, delta, LO, HI, 0);
}
};
SegmentTree *seg;
int calc_delta(int where) {
int s = 0;
s += ( (where == 0) || (elem[where - 1] > elem[where]) ? 1 : -1);
s += ( (where == W - 1) || (elem[where + 1] > elem[where]) ? 1 : -1);
return s;
}
void give_initial_chart(int H, int W, vector<int> R, vector<int> C) {
::H = H; ::W = W;
::R = R; ::C = C;
diff.resize(W);
elem.resize(W);
for (int i = 0; i < W; i++) {
elem[C[i]] = i;
}
for (int i = 0; i < W; i++) {
diff[i] = calc_delta(C[i]);
}
seg = new SegmentTree(diff);
}
int swap_seats(int a, int b) {
swap(elem[C[a]], elem[C[b]]);
swap(C[a], C[b]);
if (C[a] - 1 >= 0) seg -> modify(elem[C[a] - 1], calc_delta(C[a] - 1));
seg -> modify(a, calc_delta(C[a]));
if (C[a] + 1 < W) seg -> modify(elem[C[a] + 1], calc_delta(C[a] + 1));
if (C[b] - 1 >= 0) seg -> modify(elem[C[b] - 1], calc_delta(C[b] - 1));
seg -> modify(b, calc_delta(C[b]));
if (C[b] + 1 < W) seg -> modify(elem[C[b] + 1], calc_delta(C[b] + 1));
return seg -> get_ans();
}
