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

using namespace std;

class Token {
    public:
        int occurences;
        char value;
    private:
};

void check_validity(string user_input) {
    for (int c : user_input) {
        if (c < 'a' || c > 'z') throw runtime_error("invalid input");
    }
}

int main() {
    try {
        string input;
        vector<Token> results = {};
        int count = 1;
        cin >> input;
        check_validity(input);

        for (int i = 0; i < input.size() - 1; i++) {
            if (input[i] == input[i++]) {
                count++;
            }
            else {
                Token t;
                t.occurences = count;
                t.value = input[i];
                results.push_back(t);
            }
        }

        cout << count;

        for (Token t : results) {
            cout << t.occurences << t.value;
        }

        cout << endl;
    }
    catch (runtime_error& e) {
        cerr << "error: " << e.what() << endl;
    }

    return 0;
}