/*
 * URAL 1027
 * Wrong Answer
 */

#include <iostream>
#include <string>
#include <stdlib.h>

using namespace std;

void getout() {cout<<"NO"<<endl; exit(0);}

int main()
{
    char t[30000];
    int incomment=0,arth=0,len,i;
    while (!cin.eof())
    {
        t[0]=0;
        cin.getline(t,30000,'\n');
        len=strlen(t);
        for (i=0;i<len;i++)
        {
            if (!incomment&&t[i]=='('&&t[i+1]=='*') incomment=1,i++;
            else if (incomment)
            {
                if (t[i]=='*'&&t[i+1]==')') incomment=0,i++;
            }
            else
            {
                if (t[i]=='(') arth++;
                else if (t[i]==')') arth--;
                else if
(arth!=0&&!(t[i]=='='||t[i]=='+'||t[i]=='-'||t[i]=='*'||t[i]=='/'||(t[i]>='0'&&t[i]<='9')))
                    getout();
            }
            if (arth<0) getout;
        }
    }
    if (arth!=0||incomment) getout();
    cout<<"YES"<<endl;
    return 0;
}