#include<cstdio>

#include<algorithm>

#include<cstring>

#include<iostream>

#include<cmath>

#include<cctype>

#include<set>

#include<queue>

#include<vector>

#include<map>

using namespace std;

typedef long long LL;

inline int read() {

    int x=,f=;char ch=getchar();for(;!isdigit(ch);ch=getchar())if(ch=='-')f=-;

    for(;isdigit(ch);ch=getchar())x=x*+ch-'';return x*f;

}

const int N = ;

int dp[N];

struct Node { int id, x, l, r; } A[N], B[N];

bool cmp1(Node A, Node B) { return A.l < B.l; }

bool cmp2(Node A, Node B) { return A.x < B.x; }

bool cmp3(Node A, Node B) { return A.id < B.id; }

struct Bit{

    int mx[N], n;

    void update(int p,int v) {

        for (; p <= n; p += (p & (-p))) mx[p] = max(mx[p], v);

    }

    int query(int p) {

        int ans = ;

        for (; p; p -= (p & (-p))) ans = max(ans, mx[p]);

        return ans;

    }

    void clear(int p) {

        for (; mx[p] && p <= n; p += (p & (-p))) mx[p] = ;

    }

}bit;

void cdq(int l,int r) {

    if (l >= r) return ;

    int mid = (l + r) >> ;

    cdq(l, mid);

    sort(A + mid + , A + r + , cmp1);

    int i = l, j = mid + ;

    while (i <= mid && j <= r) {

        if (A[i].x <= A[j].l) {

            bit.update(A[i].r, dp[A[i].id]); i ++;

        }

        else {

            dp[A[j].id] = max(dp[A[j].id], bit.query(A[j].x) + ); j ++;

        }

    }

    while (j <= r) {

        dp[A[j].id] = max(dp[A[j].id], bit.query(A[j].x) + ); j ++;

    }

    for (int k = l; k < i; ++k) bit.clear(A[k].r);

    sort(A + mid + , A + r + , cmp3);

    cdq(mid + , r);

    sort(A + l, A + r + , cmp2);

}

int main() {

    int n = read(), m = read(); bit.n = n;

    for (int i = ; i <= n; ++i) A[i].id = i, A[i].x = A[i].l = A[i].r = read();

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

        int x = read(), y = read();

        A[x].l = min(A[x].l, y), A[x].r = max(A[x].r, y);

    }

    for (int i = ; i <= n; ++i) dp[i] = ;

    cdq(, n);

    int ans = ;

    for (int i = ; i <= n; ++i) ans = max(ans, dp[i]);

    cout << ans;

    return ;

}