// C.cpp: определяет точку входа для консольного приложения.
//

#include "stdafx.h"
#include <cmath>
#include <algorithm>
#include <iostream>
#include <vector>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;

vector <ll> up, down;

int main()
{
	ll last, count, n, data;
	char ch;
	cin >> last >> count >> n;
	for (int i = 0; i < n; i++)
	{
		cin >> data >> ch;
		if (ch == 'U')
			up.push_back(data);
		else
			down.push_back(data);
	}
	ll mn, ans = 0, ans1 = 0;
	for (int i = 0; i < 2 * (count + up.size()); i++)
	{
		if (ans1 == count + up.size())
		{
			cout << ans << endl;
			break;
		}
		mn = last;
		for (int j = 0; j < up.size(); j++)
			mn = min((last - up[j] != 0? last - up[j] : last), mn);
		for (int j = 0; j < down.size(); j++)
			mn = min((down[j]? down[j] : last), mn);
		for (int j = 0; j < up.size(); j++)
			up[j] += mn;
		for (int j = 0; j < down.size(); j++)
			down[j] -= mn;
		for (int j = 0; j < up.size(); j++)
			if (up[j] == last)
			{
				up.erase(up.begin() + j);
				down.push_back(last);
				ans1++;
			}
		for (int j = 0; j < down.size(); j++)
			if (down[j] == last)
			{
				down.erase(down.begin() + j);
				up.push_back(0);
			}
		ans += mn;
	}
	system("pause");
    return 0;
}