#include using namespace std; typedef pair pii; typedef long long ll; #define ITR(i,c) for(auto i=begin(c);i!=end(c);i++) #define FORE(x,arr) for(auto &x:arr) #define FOR(i,a,n) for(int i=a;i<(int)(n);i++) #define REP(i,n) FOR(i,0,n) #define ALL(c) begin(c),end(c) const int DX[4]={0,1,0,-1}, DY[4]={-1,0,1,0}; const int INF = 1e9; int main(int argc, char const *argv[]) { int s[6]; REP(i,6) {cin >> s[i];} sort(ALL(s)); double sum = s[1]+s[2]+s[3]+s[4]; printf("%f\n",sum/4); return 0; }