char brackets[3][2] = {
    {'[', ']'},
    {'(', ')'},
    {'{', '}'},
 };
 
char* isBalanced(char* s) {
    char* stack = calloc(sizeof(char), strlen(s));
    int tos = 0;
    char b;
    
    while((b = *s)) {
        for(int i = 0; i < 3; i++) {
            if(brackets[i][0] == b) {
                stack[tos++] = b;
                
            } else if(brackets[i][1] == b) {
                char left_b = stack[--tos];
                if(brackets[i][0] != left_b) {
                    return "NO";
                }
            }
        }
        ++s;
    }
    free(stack);
    return tos == 0 ? "YES" : "NO";
}