#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int main() {
  ll n,m;
  cin >> n >> m;
  vector<ll> a(m);
  for(int i = 0;i < m;i++){
    cin >> a.at(i);
  }
  vector<pair<ll,ll>> p;
  ll l,r;
  l = 0;
  r = l;
  for(int i = 0;i < m;i++){
    if(i == m - 1){
      p.push_back(make_pair(a.at(l),r - l + 1));
      break;
    }
    if(a.at(i) + 1 == a.at(i + 1)){
      r++;
    } else {
      p.push_back(make_pair(a.at(l),r - l + 1));
      r++;
      l = r;
    }
  }
  cout << p.size() << endl;
  for(int i = 0;i < (int)p.size();i++){
    cout << p.at(i).first << " " << p.at(i).second << endl;
  }
}