This documentation is automatically generated by online-judge-tools/verification-helper
#define PROBLEM "https://atcoder.jp/contests/agc001/tasks/agc001_a"
#include "../content/utils/template.h"
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cin.exceptions(cin.failbit);
int n, l[200];
cin>>n;
for(int i = 0; i < 2*n; i++)
cin>>l[i];
sort(l, l+2*n);
int ans = 0;
for(int i = 0; i < 2*n; i += 2){
ans += l[i];
}
cout<<ans<<'\n';
}
#line 1 "tests/atcoder.test.cpp"
#define PROBLEM "https://atcoder.jp/contests/agc001/tasks/agc001_a"
#line 1 "content/utils/template.h"
/**
* @brief My starter code
*/
#include <bits/stdc++.h>
#define all(x) (x).begin(), (x).end()
#define makeunique(x) (x).erase(unique((x).begin(), (x).end()), (x).end());
#ifdef LOCAL
template<typename T> void pr(T a){std::cerr<<a<<std::endl;}
template<typename T, typename... Args> void pr(T a, Args... args){std::cerr<<a<<' ',pr(args...);}
#else
template<typename... Args> void pr(Args... args){}
#endif
using namespace std;
using ll = long long;
using pii = pair<int, int>;
#line 3 "tests/atcoder.test.cpp"
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cin.exceptions(cin.failbit);
int n, l[200];
cin>>n;
for(int i = 0; i < 2*n; i++)
cin>>l[i];
sort(l, l+2*n);
int ans = 0;
for(int i = 0; i < 2*n; i += 2){
ans += l[i];
}
cout<<ans<<'\n';
}