#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
     long long int fast_exp(int base, long long int exp) 
     { if(exp==1) 
         return base; 
      else if(exp%2 == 0) 
      { long long int base1 = pow(fast_exp(base, exp/2),2); 
       if(base1 >= 1000000007) 
           return base1%1000000007; 
       else 
           return base1; }
      else
      { long long int ans = (base* pow(fast_exp(base,(exp-1)/2),2)); 
       if(ans >= 1000000007) 
           return ans%1000000007; 
       else 
           return ans; } } 
int main()
{ long long int a,b,t;
 cin>>a>>b>>t;
 long int k=(a+b)/2; 
 cout<<k;
return 0;
}
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */