#include <stdio.h>
#include <malloc.h>

int main() {
    int rozmer, result=0;
    scanf("%d", &rozmer);

    char *m = (char*)malloc( sizeof(char)*rozmer );

    scanf("%c", &m[0]);
    for ( int i = 0; i < rozmer; i++ ) {
        scanf("%c", &m[i]);
    }

    for (int i = 0; i < rozmer-1; i++) {
        if ( m[i] == ')' ) {
            if ( m[i+1] == ')' ) {
                result++;
            }
        }
        if ( m[i] == '(' ) {
            if ( m[i+1] == ')' ) {
                result++;
            }
        }
    }

    free(m);

    printf("%d", result);

    return 0;
}