// To compile: gcc --std=gnu++11   freq.cpp -lstdc++  -o freq

#include <iostream>
#include <map>
#include <vector>
#include <algorithm>
#include <string>
#include <fstream>
#include <cctype>

using namespace std;


int main(int argc, char *argv[]) {
	ifstream in;
	ofstream out;

	if (argc < 3) {
		cerr << "too less parametrs \n";
		return -1;
	}

	in.open(argv[1]);
	if (!in.is_open()) {
		cerr << "can't open "  << argv[1] << "\n";
	}

	out.open(argv[2]);
	if (!out.is_open()) {
		cerr << "can't open "  << argv[2] << "\n";
	}

	string line;
	map<string, int> word_map;
	while (getline(in, line)) {
		string lc_word;
		for(auto ch : line) {
			if (isalpha(ch)) {
				lc_word += tolower(ch);
				continue;
			}
			if (lc_word.size() > 0) {
				word_map[lc_word]++;
				lc_word = "";
			}
		}
		if (lc_word.size() > 0) {
			word_map[lc_word]++;
			lc_word = "";
		}
	}

	std::vector<pair<string, int>> out_vector;
	for (auto item : word_map) {
		out_vector.push_back(item);
	}
	stable_sort(out_vector.begin(), out_vector.end(), [](const pair<string, int>& a, const pair<string, int>& b)->bool{return a.second > b.second;});

	for (auto item : out_vector) {
		out << item.second << " " << item.first << "\n";
	}

	in.close();
	out.close();

	return 0;
}