#include <bits/stdc++.h>

// #include <atcoder/fenwicktree.hpp>
// #include <atcoder/segtree.hpp>
// #include <atcoder/modint.hpp>
// #include <atcoder/dsu.hpp>
// #include <atcoder/lazysegtree.hpp>

// using namespace atcoder;
using namespace std;
using ll = long long;
using ull = unsigned long long;
template <class T>
using max_heap = priority_queue<T>;
template <class T>
using min_heap = priority_queue<T, vector<T>, greater<>>;
ll ll_min = numeric_limits<ll>::min();
ll ll_max = numeric_limits<ll>::max();
ll ALPHABET_N = 26;
// using mint = modint998244353;
#define rep(i, n) for (ll i = (ll)0; i < (ll)n; i++)
#define rep_(i, k, n) for (ll i = (ll)k; i < (ll)n; i++)
#define all(a) a.begin(), a.end()

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	ll n, m;
	cin >> n >> m;
	vector<pair<ll, ll>> ans;
	rep(_, m)
	{
		ll a;
		cin >> a;
		if (ans.empty() || (ans.back().first + ans.back().second) != a)
		{
			ans.push_back({a, 1});
		}
		else
		{
			ans.back().second++;
		}
	}
	cout << ans.size() << endl;
	for (auto [a, b] : ans)
	{
		cout << a << " " << b << endl;
	}
	return 0;
}