#include <stdio.h>
#include <string.h>

int main(void) {
    char ch[55];
    scanf("%s", ch);

    int len = strlen(ch);
    int ans = 0;
    int current = 0;
    for(int i = 1; i < len; i++){
        if(ch[i] == '('){
            current++;
            if(current > ans)
                ans = current;
        }
        else
            current--;
    }
    printf("%d", ans+1);
    return 0;
}