#include <stdio.h>

int f(){
    int count = 0;
    // printf("1: read (: %d\n", count);
    while (getchar() == '('){
        count++;
        // printf("2: read (: %d\n", count);
    }


    int S = 1;
    while (count > 0){
        if (getchar() == ')'){
            // printf("2: read ): %d\n", count);
            S++;
            count--;
        }
        else{
            S *= f();
        }
    }
    return S;
}


int main(int argc, char const *argv[]){
    int len;
    if (1 != scanf("%d ", &len)){
        return 1;
    }

    int S = 1;
    while (getchar() != '\n'){
        S *= f();
    }
    printf("%d\n", S);
    return 0;
}