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

int scoreOfParentheses(char *s) {
    int stack[50], top = -1;
    stack[++top] = 0;  // base score

    for (int i = 0; s[i] != '\0'; i++) {
        if (s[i] == '(') {
            stack[++top] = 0;   // push new score frame
        }
        else if (s[i] == ')') {
            if (top < 1) return -1;  // unbalanced
            int v = stack[top--];    // inner score
            int w = stack[top];
            stack[top] = w + (v == 0 ? 1 : 2 * v);
        }
        else {
            return -1;  // invalid character
        }
    }

    if (top != 0) return -1; // not fully reduced
    return stack[top];
}

int main() {
    char s[35];
    scanf("%s", s);

    int len = strlen(s);
    if (len < 2 || len > 30) {
        printf("Invalid input\n");
        return 0;
    }

    int result = scoreOfParentheses(s);
    if (result == -1) {
        printf("Invalid input\n");
    } else {
        printf("%d\n", result);
    }

    return 0;