#include <cstdio>
#include <cstdlib>
#include <iostream>
#include <algorithm>
#include <vector>
#include <string>
#include <string.h>
#include <queue>
#include <stack>
#include <deque>
#include <map>
#include <set>
#include <cmath>
#include <sstream>
#include <ctime>

#define pb push_back
#define mp make_pair
#define PI 3.1415926535897932384626433832795
#define ALL(x) x.begin(), x.end()
#define F first
#define S second
#define m0(x) memset(x,0,sizeof(x))
#define m1(x) memset(x,-1,sizeof(x))
#define pw(x) (1ull<<(x))

using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int,int> pii;
const int INF = 2147483647;
const ll LLINF = 9223372036854775807LL;

template< typename Container>
typename Container::value_type sum(Container x) {
  typename Container::value_type ans = *x.begin();
  for (typename Container::iterator it = ++x.begin();it!=x.end();it++) ans+=*it;
  return ans;
}

template< typename Container>
typename Container::value_type returnLastRepeat(Container cont) {
  for (typename Container::reverse_iterator rIt1 = cont.rbegin(); rIt1 != cont.rend(); rIt1++) {
    typename Container::reverse_iterator rIt2 = rIt1;
    rIt2++;
    for (; rIt2 != cont.rend(); rIt2++) {
      if (*rIt1 == *rIt2) {
        cout << *rIt1 << " " << *rIt2 << "\n";
        return *rIt1;
      }
    }
  }
  cout << "Error! There are no repeating elements in the container! " << endl;
  exit(0);
}

int main() {
  //freopen("input.txt", "r", stdin);
  //freopen("output.txt", "w", stdout);
  int a[4] = {1, 2, 3};
  vector<int> x(a, a+4);
  cout << sum(x) << "\n";

  double mass1[5] = {1.3, 5.7, 9.4, 5.8, 10.3};
  set<double> cont2 (mass1, mass1+5);
  double rep_set = returnLastRepeat(cont2);
  cout << rep_set << endl;
  return 0;
}