#include <iostream>
#include <vector>
using namespace std;

int main()
{
	int n,k;
	int cnt=0;
	cin >>n>>k;
	vector<int> x,y;
	for(int i=0;i<k;i++){
		int a,b;
		cin>>a>>b;
		x.push_back(a);
		y.push_back(b);
	}

	vector<int> goal;
	for(int i=0;i<n;i++){
		int goal;
		cin>>goal;

		int pos=i+1;
		for(int j=0;j<k+cnt;j++){
			if(x[j]==pos){
				pos++;
			}else if(y[j]==pos){
				pos--;
			}
		}
		while(pos!=goal){
			if(pos>goal){
				x.push_back(pos-1);
				y.push_back(pos);
				pos--;
			}else if(pos<goal){
				x.push_back(pos);
				y.push_back(pos+1);
				pos++;
			}
			cnt++;
		}
	}

	cout<<cnt<<endl;
	for(int i=k;i<k+cnt;i++){
		cout<<x[i]<<" "<<y[i]<<endl;
	}

	return 0;
}