#include <stdio.h>

int main()
{
    int total = 0;
    int input1;
    scanf("%d", &input1);
    char* input2 = malloc(input1 + 2);
    scanf("%s", input2);
    input2[input1] = '\0';
    for (int i = 1; i < input1; i++)
    {
        if (input2[i] == ')')
        {
            total++;
        }
    }
    printf("%d", total);
    return 0;
}