#28599: _CPP
11030067@mail.hpsh.tp.edu.tw
(和平110級鄧雨珊)
#include <iostream>
#include <sstream>
#include <cstdio>
using namespace std;
int main(){
string s;
while (getline(cin, s)){
stringstream ss(s);
char s1[100];
int id;
double t, ans=0;
while (ss >> s1){
sscanf(s1, "%d:%lf", &id, &t);
if (id%2==1){
ans+=t;
}
else {
ans-=t;
}
}
cout << ans <<endl;
}
}