#include #include #include #include #include #include #include #include #include #include using namespace std; #define rep(i, n) for (int i = 0; i < (int)(n); i++) #define repe(i,x,n) for(int i=x; i<(n); ++i) using ll = long long; using P = pair; #define pai 3.1415926535897932384 #define INF 10010010000 #define _GLIBCXX_DEBUG #define All(a) (a).begin(),(a).end() #define rAll(a) (a).rbegin(),(a).rend() #define pb push_back #define mk make_pair #define yes cout << "Yes" << endl; #define no cout << "No" << endl; #define mod 998244353 #define mod2 1000000007 #define deci cout << fixed << setprecision(10); #define nextP next_permutation #define em emplace_back int main() { int a,b,c; cin >> a >> b >> c; cout << (a+b+c) / 2 << endl; return 0; }