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#include <cstdio>
#include <vector>

std::vector<int> g[301];
bool del[301];

int ans(int n, int k) {
	int dp[301] = {0};
	bool con[301] = {0};

	for(int i = n; i >= 0; i--)
		if(!del[i])
			for(auto j : g[i])
				if(!del[j])
					dp[i]= std::max(dp[i], dp[j]+1);

	if(k == 0) return dp[0];

	int ret = 1000;

	for(auto j : g[0])
		if(!del[j] && dp[0] == dp[j]+1)
			con[j] = true;

	for(int i = 1; i <= n; i++)
		if(!del[i] && con[i]) {

			del[i] = true;
			ret = std::min(ret, ans(n, k-1));
			del[i] = false;

			for(auto j : g[i])
				if(!del[j] && dp[i] == dp[j]+1)
					con[j] = true;
		}


	return ret;
}

int main() {
	int n, m, k;
	scanf("%i%i%i", &n, &m, &k);

	while(m--) {
		int a, b;
		scanf("%i%i", &a, &b);
		g[a].push_back(b);
	}

	for(int i = 1; i <= n; i++)
		g[0].push_back(i);

	printf("%i", ans(n, k));
}