#include<stdio.h>int
main(){ inti,top; charch[1005],str[1005]; while(scanf("%s",ch)==1) { top=0; for(i=0;ch[i]!='\0';i++) { if(ch[i]=='(')
str[top++]=ch[i];
else if(ch[i]==')')
top--;
else
break; } printf("%d\n",top); } return0;}