#include<bits/stdc++.h>
using namespace std;
int main()
{
char a,chuchun=0;
double ans=0,xishu=0,a1=1,a2=1,a3=0,cishu=0;
while(cin>>a)
{
	if(a>='1'&&a<='9')
	cishu=cishu*10+(a-'0');	
	if(a>='a'&&a<='z')
	{
	  chuchun=a;	
	  xishu+=a3*a2*a1;
	  a3=0;
	}	
	if(a=='+')
	{
		cishu+=a1*a2*a3;
		a1=1;
		a3=0;
	}
	if(a=='-')
	{
		cishu+=a1*a2*a3;
		a1=-1;
		a3=0;
	}
	if(a=='=')
	{
	 cishu+=a1*a2*a3;
	 a3=0;
	 a1=-1;
	 a2=1;	
	}	
}
cishu=cishu+a1*a2*a3;
if(cishu==0||xishu==0)
{
cout<<"0.000";
return 0;
}
cout<<fixed<<setprecision(3)<<chuchun<<(cishu)*-1.0/(xishu);
return 0;
}