#include <bits/stdc++.h>
#include <cstdlib>
#include <math.h>
using namespace std;

using ll = long long;


int main(){
    ll n,m;
    cin >> n >> m;
    vector<pair<ll,ll>>ans;
    vector<ll>a(m);
    for(int i=0;i<m;i++)cin >> a[i];
    ll curs=a[0],curl=1;
    for(int i=0;i<m-1;i++){
        if(a[i]+1==a[i+1]){
            curl+=1;
        }else{
            ans.push_back({curs,curl});
            curs=a[i+1];
            curl=1;
        }
    }
    ans.push_back({curs,curl});
    cout << ans.size() << endl;
    for(auto[i,j]:ans)cout << i << " " << j << endl;
    return 0;
}