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
#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstring>
#include <vector>
#include <set>
#include <map>
#include <cmath>
#include <list>
#include <ctime>
#include <sstream>
#include <queue>
#include <stack>
#include <bitset>
#include <unordered_set>
#include <unordered_map>
using namespace std;
typedef vector<int> vi;
typedef pair<int,int> pii;
typedef long long ll;
typedef short int sint;
#define FOR(x, b, e) for(int x=(b); x<=(e); ++x)
#define FORD(x, b, e) for(int x=((int)(b))-1; x>=(e); --x)
#define REP(x, n) for(int x=0; x<(n); ++x)
#define ALL(c) c.begin(),c.end()
#define SIZE(x) ((int)((x).size()))
#define PB push_back
#define ST first
#define ND second
#define mp(x,y) make_pair(x,y)
#define DEBUG 1
#define debug(x) {if (DEBUG)cerr <<#x <<" = " <<x <<endl; }
#define debugv(x) {if (DEBUG) {cerr <<#x <<" = "; FOREACH(it, (x)) cerr <<*it <<", "; cout <<endl; }}
#define REMAX(a,b) (a)=max((a),(b));
#define REMIN(a,b) (a)=min((a),(b));
#define wez(n) int (n); scanf("%d",&(n));
#define wez2(n,m) int (n),(m); scanf("%d %d",&(n),&(m));

const int N = 301;
vi za[N];
int maxD[N];
int pre[N];
bool del[N];
int n, m, k;

int solve(int kp) {
	FOR(i, 1, n) if (!del[i]) {maxD[i] = 1; } else {maxD[i] = 0;}
	int najw = -1, maxDist = 0;
	FOR(i, 1, n) {
		if (del[i]) {
			// this element is deleted
			continue;
		}
		if (maxD[i] > maxDist) {
			najw = i;
			maxDist = maxD[i];
		}
		for (auto x : za[i]) {
			if (!del[x] && maxD[i] + 1 > maxD[x]) {
				pre[x] = i;
				maxD[x] = maxD[i] + 1;
			}
		}
	}
	if (kp == 0) {
		// if (maxDist < 11) {
		// 	printf("%d for: ", maxDist); for (auto de : del) printf("%d ", de); printf("\n");
		// }
		return maxDist;
	}
	// printf("max dist: %d\n", maxDist);
	vi kand;
	REP(i, maxDist) {
		kand.PB(najw);
		najw = pre[najw];
	}
	int nRes = N;
	for (auto kandydat : kand) {
		del[kandydat] = true;
		int res = solve(kp - 1);
		nRes = min(nRes, res);
		del[kandydat] = false;
	}
	return nRes;
}

int main() {
	scanf("%d %d %d", &n, &m, &k);
	REP(i, m) {
		int x, y;
		scanf("%d %d", &x, &y);
		za[x].PB(y);
	}
	int res = solve(k);
	printf("%d\n", res);
	return 0;
}