DAUCHAN C++

#include <bits/stdc++.h>
using namespace std;

int f[50005];
string s;
void nhap_tinhf()
{
    getline(cin,s);
    f[0]=0;
    for(int i=1;i<=s.length()-1;i++)
        if(s[i]=='('&&s[i-1]=='(')
            f[i]=f[i-1]+1;
        else
            f[i]=f[i-1];
}

void giai()
{
    int res=0;
    for(int i=1;i<=s.length()-1;i++)
        if(s[i]==')'&&s[i-1]==')')
            res=res+f[i];
    cout<<res;
}

int main()
{
    freopen("dauchan.inp","r",stdin);
    freopen("dauchan.out","w",stdout);
    nhap_tinhf();
    giai();
}