Code：

#include<algorithm>

#include<iostream>

#include<cstdlib>

#include<cstdio>

#include<cmath>

#include<cstring>

using namespace std;

int n,m;

#define MAXN 100010

struct num

{

	int id,a,maxn,minn;

}w[MAXN];

int f[MAXN];

bool cmp_maxn(num x,num y){return x.maxn < y.maxn;}

bool cmp_a(num x,num y){return x.a < y.a;}

bool cmp_id(num x,num y){return x.id < y.id;}

int mx = 0;

struct BIT

{

	int c[MAXN];

	int lowbit(int x){return (x&(-x));}

	void add(int p,int k){for(int i = p;i <= mx;i += lowbit(i))c[i] = max(c[i],k);return;}

	int query(int p){int res = 0;for(int i = p;i >= 1;i -= lowbit(i))res = max(res,c[i]);return res;}

	void reset(int p){for(int i = p;i <= mx;i += lowbit(i))c[i] = 0;return;}

}t;

void cdq(int l,int r)

{

	if(l == r)return;

	int mid = (l + r) / 2;

	cdq(l,mid);

	sort(w + l,w + mid + 1,cmp_maxn);

	sort(w + mid + 1,w + r + 1,cmp_a);

	int i = l,j = mid + 1;

	for(;i <= mid && j <= r;)

	{

		if(w[i].maxn > w[j].a)

		{

			f[w[j].id] = max(f[w[j].id],t.query(w[j].minn) + 1);

			++j;

		}

		else

		{

			t.add(w[i].a,f[w[i].id]);

			++i;

		}

	}

	for(;j <= r;++j)f[w[j].id] = max(f[w[j].id],t.query(w[j].minn) + 1);

	for(int k = l;k <= mid;++k)t.reset(w[k].a);

	sort(w + mid + 1,w + r + 1,cmp_id);

	cdq(mid + 1,r);

	return;

}

int main()

{

	scanf("%d%d",&n,&m);

	for(int i = 1;i <= n;++i)

	{

		scanf("%d",&w[i].a);

		w[i].minn = w[i].maxn = w[i].a;

		f[i] = 1;

		w[i].id = i;

		mx = max(mx,w[i].a);

	}

	int p,k;

	for(int i = 1;i <= m;++i)

	{

		scanf("%d%d",&p,&k);

		w[p].minn = min(w[p].minn,k);

		w[p].maxn = max(w[p].maxn,k);

		mx = max(mx,k);

	}

	cdq(1,n);

	int ans = 0;

	for(int i = 1;i <= n;++i)

		ans = max(ans,f[i]);

	cout << ans << endl;

	return 0;

}