1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
#include <algorithm>
#include <iostream>
#include <cassert>
#include <vector>
#include <cstdio>
#include <array>
#include <deque>
#include <cmath>
#include <stack>
#include <queue>
#include <set>
#include <map>
namespace {
	using namespace std;

	typedef vector<int> vint;
	typedef long long unsigned ulo;
	typedef long long lint;
	
	void __attribute__((unused)) spacje(int k) {
		int magic;
		static stack<int*> stos;
		while (!stos.empty() && stos.top() <= &magic) stos.pop();
		stos.push(&magic);
		for (int n = k * stos.size(); n--;) printf(" ");
	}
	
	#define BOTH(x) for (int x = 0; x < 2; ++x)
	
	#define UPlt(xx, yy) (xx) = min(xx, yy)
	#define UPgt(xx, yy) (xx) = max(xx, yy)
	
	struct in_t {
		template<class T>
		operator T () {
			static bool __attribute__((unused)) dummy = ios_base::sync_with_stdio(false);
			T x;
			cin >> x;
			return x;
		}
	};
	in_t __attribute__((unused)) in;
	
	class Print {
		ostream & os;
		bool nfirst;
	 public:
		Print(ostream & os = cout) : os(os), nfirst(false) {}
		~Print() { os << endl; }
		template<class T> Print & operator , (T const& e) {
			if (nfirst) os << " "; os << e; nfirst = true; return *this; }
	};
	
	#define print Print{cout},
	#define prerr Print{cerr},
	
	template <class T>
	struct Range {
		struct Intit {
			T x; Intit(T x) : x(x) {}
			T & operator * () { return x; };
			bool operator != (Intit other) { return x < other.x; }
			void operator ++ () { ++x; }
		};
		
		T b, e;
		explicit Range(T n) : b(0), e(n) {}
		Range(T b, T e) : b(b), e(e) {}
		Intit begin() { return b; }
		Intit end() { return e; }
	};
	
	template <class T>
	Range<T> range(T n) { return Range<T>(n); }
	
	template <class T>
	Range<T> range(T b, T e) { return Range<T>(b, e); }

	template <class T>
	Range<T> inclusive(T b, T e) { return Range<T>(b, e + 1); }
	
	#define _ __attribute__((unused)) _
};

#define dprintf if (1) spacje(2), printf

struct P {
	short beg;
	short end;
};

struct PK {
	int cost;
	short beg;
	short end;
	
	bool operator < (PK const& pk) const {
		return tie(cost, beg, end) < tie(pk.cost, pk.beg, pk.end);
	}
};

int main() {
	lint suma = 0;
	vector<vint> costs;
	set<PK> mincosts;
	short n = in;
	costs.resize(n+1);
	for (short beg : range(n+1)) {
		costs[beg].resize(beg+1);
		for (short end : inclusive(short(beg+1), n)) {
			int c = in;
			costs[beg].push_back(c);
			mincosts.insert({c, beg, short(end)});
		}
	}
	
	vector<vector<bool>> known(n+1, vector<bool>(n+1));
	for (short i : range(n+1)) known[i][i] = true;
	
	while (!mincosts.empty()) {
		PK ten = *mincosts.begin();
		mincosts.erase(mincosts.begin());
		suma += ten.cost;
		vector<P> tomark = {{ten.beg, ten.end}};
		known[ten.beg][ten.end] = true;
		known[ten.end][ten.beg] = true;
		while (!tomark.empty()) {
			vector<P> nowe;
			auto markadd = [&](short a, short b) {
				if (a > b) swap(a, b);
				known[a][b] = true;
				known[b][a] = true;
				nowe.push_back({a,b});
				mincosts.erase(mincosts.find({costs[a][b], a, b}));
			};
			for (P p : tomark) {
				vector<bool> & knop = known[p.beg];
				vector<bool> & knok = known[p.end];
				for (short x : range(n+1)) {
					bool knopx = knop[x];
					bool knokx = knok[x];
					if (knopx && !knokx) markadd(p.end, x);
					if (knokx && !knopx) markadd(p.beg, x);
				}
			}
			tomark = move(nowe);
		}
	}
	
	print suma;
	
	return 0;
}