There are N squares numbered 1 to N from left to right. Each square has a character written on it, and Square i has a letter s_i. Besides, there is initially one golem on each square.

Snuke cast Q spells to move the golems.

The i-th spell consisted of two characters t_i and d_i, where d_i is `L` or `R`. When Snuke cast this spell, for each square with the character t_i, all golems on that square moved to the square adjacent to the left if d_i is `L`, and moved to the square adjacent to the right if d_i is `R`.

However, when a golem tried to move left from Square 1 or move right from Square N, it disappeared.

Find the number of golems remaining after Snuke cast the Q spells.

Constraints

* 1 \leq N,Q \leq 2 \times 10^{5}
* |s| = N
* s_i and t_i are uppercase English letters.
* d_i is `L` or `R`.

Input

Input is given from Standard Input in the following format:


N Q
s
t_1 d_1
\vdots
t_{Q} d_Q


Output

Print the answer.

Examples

Input

3 4
ABC
A L
B L
B R
A R


Output

2


Input

8 3
AABCBDBA
A L
B R
A R


Output

5


Input

10 15
SNCZWRCEWB
B R
R R
E R
W R
Z L
S R
Q L
W L
B R
C L
A L
N L
E R
Z L
S L


Output

3
#include<bits/stdc++.h>
/**/

using namespace std;


int main(){
	long long int N, Q;
	cin >> N >> Q;
	auto now = vector<long long int>(N, 1);
	string S;
	cin >> S;

	vector<pair<char, char>>Query(Q);
	for( size_t i = 0; i < Q; i++ ){
		cin >> Query[i].first >> Query[i].second;
	}
	long long int begin = -1, end = N;
	for( auto now = Query.rbegin(); now < Query.rend(); now++ ){
		auto ope = *now;
		if( 0 <= begin + 1 && begin + 1 < N&& ope.first == S[begin + 1] && ope.second == 'L' ){
			begin++;
		} else if( 0 <= begin && begin < N&&  ope.first == S[begin] && ope.second == 'R' ){
			begin--;
		}

		if( 0 <= end && end < N&& ope.first == S[end] && ope.second == 'L' ){
			end++;
		} else if( 0 <= end - 1 && end - 1 < N&&  ope.first == S[end - 1] && ope.second == 'R' ){
			end--;
		}
		if( begin + 1 == end ){
			break;
		}
	//cout << begin << " " << end << endl;
	}
	cout << end - begin - 1 << endl;
}
