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

int main() {
    int N, M;
    cin >> N >> M;

    vector<int> A(M);
    for (int i = 0; i < M; i++) {
        cin >> A[i];
    }

    vector<pair<int, int>> ans{{A[0], 1}};
    
    for (int i = 0; i < M - 1; i++) {
        if (A[i + 1] - A[i] == 1) {
            ans.back().second++;
        } else {
            ans.push_back({A[i + 1], 1});
        }
    }

    cout << ans.size() << endl;
    for (auto &[s, l] : ans) {
        cout << s << " " << l << endl;
    }
}