##第八个点WA了，不知道为什么，用的二分图染色法 求大佬调

#include<iostream>
#include<cstring>
using namespace std;
const int N = 1e5 + 10;
int n, m;
int h[N], e[N], ne[N], idx = 0;
int ans = 0, minv = 0;
int color[N];
int st[N];
int addbit() {
	int a1 = 0, a2 = 0; int k;
	for (int i = 1; i <= n; i++) {
		if (color[i] == 1&&!st[i]) {
			st[i] = 1;
			a1++;
		}
		if (color[i] == 0&&!st[i]) {
			st[i] = 1;
			a2++; 
		}
	}
	k = min(a1, a2);
	return k;
}
bool dfs(int u, int c) {
	color[u] = c;
	for (int i = h[u]; i != -1; i = ne[i]) {
		int j = e[i];
		if (color[j]==-1) {
			if (!dfs(j, !c))return false;
		}
		else if (color[j] == c)return false;
	}
	return true;
}
bool check() {
	bool flag = true;
	for (int i = 1; i <= n; i++) {
		if (color[i]==-1) {
			flag = dfs(i, 0);
			if (flag) {
				ans += addbit();
			}
		}
	}
	return flag;
}
void add(int a, int b) {
	e[idx] = b;
	ne[idx] = h[a];
	h[a] = idx++;
}
int main() {
	memset(h, -1, sizeof h);
	cin >> n >> m;
	while (m--) {
		int a, b;
		cin >> a >> b;
		add(a, b);
		add(b, a);
	}
	memset(color, -1, sizeof color);
	if (check()) {
		cout << ans;
	}
	else cout << "Impossible";
}