// editor1#include <stdio.h>
#include <string.h>
int main() 
{
    int n;
    scanf("%d", &n);
    char glyphs[n + 1]; 
    scanf("%s", glyphs);
    if (strlen(glyphs) != n) 
    {
        printf("Invalid input\n");
        return 0;
    }
    for (int i = 0; i < n; i++) 
    {
        if (glyphs[i] != '(' && glyphs[i] != ')') 
        {
            printf("Invalid input\n");
            return 0;
        }
    }
    int stack[n]; 
    int top = -1; 
    int maxLength = 0;
    stack[++top] = -1;
    for (int i = 0; i < n; i++) 
    {
        if (glyphs[i] == '(') 
        {
            stack[++top] = i;
        } 
        else 
        {
            top--;
            if (top == -1) 
            {
                stack[++top] = i;
            } 
            else 
            {
                int length = i - stack[top];
                if (length > maxLength)
                    maxLength = length;
            }
        }
    }
    printf("%d\n", maxLength);
    return 0;
}