def dfs(node, prev_node):
global flag
if node not in visited:
if flag:
visited.add(node)
else:
flag = True
ret = True
for n in arcs[node]:
if prev_node != n:
ret = ret and dfs(n,node)
return ret
cities, roads = list(map(int,input().split()))
arcs = {k+1: [] for k in range(cities)}
flag = False
visited = set()
min = 0
for _ in range(roads):
a,b = list(map(int,input().split()))
arcs[a].append(b)
arcs[b].append(a)
for n in range(1,cities+1):
if n not in visited:
if(dfs(n,0)):
min +=1
print(min)
#include <bits/stdc++.h>
#define rep(i,n) for (long long i=0; i<n; ++i)
#define isodd %2==1
#define iseven %2==0
#define ll long long
#define ld long double
#define pb push_back
#define mp make_pair
#define all(v) v.begin(),v.end()
#define back(v) v.rbegin(),v.rend()
#define vi vector<ll>
#define vb vector<bool>
#define IOS ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0)
using namespace std;
bool dfs(ll node,vb &vis,vector<vi> &adj,ll parent){
vis[node]= true;
bool ans = false;
for(auto it:adj[node]){
if(!vis[it]){
if(dfs(it,vis,adj,node)) {
ans= true;
}
}
else if(it!=parent) {
ans= true;
};
}
return ans;
}
void sol(){
ll n,m;
cin>>n>>m;
vector<vi> adj(n+1);
for (ll i = 0; i < m; i++)
{
ll x,y;cin>>x>>y;
adj[x].push_back(y);
adj[y].push_back(x);
}
ll cnt=0;
vb vis(n+1,0);
for (ll i = 1; i <= n; i++)
{
if(!vis[i]){
if(!dfs(i,vis,adj,-1)){
cnt++;
}
}
}
cout<<cnt<<'\n';
}
int main()
{IOS;
sol();
return 0;
}961A - Tetris | 1635B - Avoid Local Maximums |
20A - BerOS file system | 1637A - Sorting Parts |
509A - Maximum in Table | 1647C - Madoka and Childish Pranks |
689B - Mike and Shortcuts | 379B - New Year Present |
1498A - GCD Sum | 1277C - As Simple as One and Two |
1301A - Three Strings | 460A - Vasya and Socks |
1624C - Division by Two and Permutation | 1288A - Deadline |
1617A - Forbidden Subsequence | 914A - Perfect Squares |
873D - Merge Sort | 1251A - Broken Keyboard |
463B - Caisa and Pylons | 584A - Olesya and Rodion |
799A - Carrot Cakes | 1569B - Chess Tournament |
1047B - Cover Points | 1381B - Unmerge |
1256A - Payment Without Change | 908B - New Year and Buggy Bot |
979A - Pizza Pizza Pizza | 731A - Night at the Museum |
742A - Arpa’s hard exam and Mehrdad’s naive cheat | 1492A - Three swimmers |