#include <iostream>
#include <string>
#include <vector>

using namespace std;

int main()
{
    int n, m;
    cin >> n >> m;
    int a, p, s, l;
    vector<pair<int, int>> v;
    for (int i = 0; i < m; i++) {
        cin >> a;
        if (i == 0) {
            p = a;
            s = a;
            l = 1;
            continue;
        }
        if (a-p == 1) l++;
        else {
            v.emplace_back(s, l);
            s = a;
            l = 1;
        }
        p = a;
    }
    v.emplace_back(s, l);
    cout << v.size() << endl;
    for (auto [s, l]: v)
        cout << s << " " << l << "\n";
    return 0;
}