#include <stdio.h>
int main(void){
int i = 0, k = 0, l = 1;
int N = 0, K = 0;
char S[10000];
scanf ("%d%d", &N, &K);
for ( i = 0; i < N; i++){
	scanf ("%s",&S[i]);
}

if ( S[K - 1] == '('){
	for ( i = K - 1; l != 0; i++){
		k += ( S[i] == 40) ? 1 : -1;
		l = (k == 0) ? 0 : l; 
	}
}else{
	for ( i = K -1; l != 0; i--){
		k += ( S[i] == 40) ? 1 : -1;
		l = (k == 0) ? 0 : l;
	}
	i+= 2;
}
printf ("%d",i);
	return 0;
}