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
#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
#include "message.h"
#include "teatr.h"
using namespace std;

#define FOR(i,a,n) for (auto i ## __ = (n), i = (a); i <= i ## __; ++i)
#define FORD(i,a,n) for (auto i ## __ = (n), i = (a); i >= i ## __; --i)
#define REP(i,n) FOR(i,0, n - 1)
#define ALL(h) begin(h), end(h)
#define EB emplace_back
#define X first
#define Y second
#define V vector
#define tpv typedef V<

typedef long long LL;
typedef pair<int, int> PII;
tpv int> VI;
tpv VI> VVI;
tpv PII> VPII;
tpv LL> VLL;

constexpr char nl = '\n';
#define endl nl
#define ris return *this
#define tem template<class t

tem, class u> inline void mini(t& a, u&& b) { if (b < a) a = b; }
tem, class u> inline void maxi(t& a, u&& b) { if (b > a) a = b; }
int ceil2(int h) { return h < 2 ? 1 : 1 << (sizeof(h) * 8 - __builtin_clz(h - 1)); }

tem> struct Dump { t a, b; };
tem> auto dump(t&& h) -> Dump<decltype(begin(h))> { return {ALL(h)}; }
tem> auto stub(t* h) -> decltype(cerr << *h, 0);
tem> char stub(...);
#define enif(o) tem> typename enable_if<sizeof stub<t>(0) o 1, debug&>::type operator<<(t h)
#define dor > debug& operator<<
struct debug {
#ifdef DEBUG
#define deb debug()
	~debug() { cerr << nl; }
	enif(!=) { cerr << boolalpha << h; ris; }
	enif(==) {
		*this << '{';
		for (auto a = begin(h), b = end(h); a != b;)
			*this << *a++ << &" "[a == b];
		ris << '}';
	}
	tem, class u dor(pair<t, u> p) { ris << '(' << p.X << ", " << p.Y << ')'; }
	tem dor(Dump<t> d) {
		*this << "{\n";
		for (t a = d.a, c = a; a != d.b; ++a)
			*this << "  " << distance(c, a) << ": " << *a << nl;
		ris << '}';
	}
#else
	operator int() { return 0; }
#define deb 0 and debug()
	tem dor(t&&) { ris; }
#endif
};

#define imie(h...) #h ": " << (h) << " "
#define LOG(h...) deb << imie(h)
#define DOG(h...) deb << #h ": " << dump(h) << " "

const int N = 1000010;
int ile[N + 1];
int T[N + 1];

void add(int x, int val) {
	while (x <= N) {
		T[x] += val;
		x += (x & -x);
	}
}

int query(int x) {
	int res=0;
	while (x > 0) {
		res += T[x];
		x -= (x & -x);
	}
	return res;
}

// int GetN() { return 100000000; }
// int GetElement(int i) {
// 	double t = 0;
// 	for (int id = 0; id < 40; id++)
// 		t += sin(1);
// 	return (i * 1ll * i) % int(1e6) + 1 + (t > 0);
// }

int main() {
	
	if(MyNodeId() == 0) {
		int nodes = NumberOfNodes();
		int n = GetN();
		
		int rem = n, prev = 0;
		FOR(i, 1, nodes - 1) {
			int giv = rem / (nodes - i);
			// if (i == nodes - 1) {
				
			PutInt(i, prev); PutInt(i, prev + giv - 1);
			Send(i);
			// }
			prev += giv;
			rem -= giv;
		}
		
		LL sum = 0;
		FOR (i, 1, nodes - 1) {
			// if (i == nodes - 1) {
				
			Receive(i);
			sum += GetLL(i);
			// }
		}
		
		printf("%lld\n", (LL)n * (n - 1) / 2 - sum);
	}
	else/* if (MyNodeId() == NumberOfNodes() - 1)*/ {
		Receive(0);
		int a = GetInt(0), b = GetInt(0);
		// LL s = 0;
		// REP (i, 100000000)
		// 	s += GetElement(i);
		// if (s == 0) cout << s << endl;
		LL res = 0;
		if (a <= b) {
			// cerr << a << endl;
			REP (i, a)
				ile[GetElement(i)]++;
			
			REP (i, N)
				if (ile[i])
					add(i, ile[i]);
			FOR (i, a, b) {
				int q = GetElement(i);
				res += query(q);
				add(q, 1);
			}
		}
		PutLL(0, res);
		Send(0);
	}
	
	return 0;
}