#include <bits/stdc++.h>
using namespace std;
typedef pair<int,int> ii;
const int MAXN = 1e5 + 10;
const int MAXM = 2*1e5 + 10;
int e1[MAXM],e2[MAXM],pai[MAXN],ligapai[MAXN],peso[MAXN],N,M,ans;
int possivel,last,oldw[MAXM],oldz[MAXM],oldpai[MAXM],oldliga[MAXM],oldpeso[MAXM],oldpossivel[MAXM];
int find(int x){
if(x == pai[x]) return x;
return find(pai[x]);
}
int parity(int x){
if(x == pai[x]) return 0;
return (ligapai[x] ^ parity(pai[x]));
}
void join(int x,int y){
int w = find(x), z = find(y),px = parity(x),py = parity(y);
if(peso[w] < peso[z]){
swap(w,z);
swap(px,py);
swap(x,y);
}
last++;
oldw[last] = w;
oldz[last] = z;
oldpai[last] = pai[z];
oldliga[last] = ligapai[z];
oldpeso[last] = peso[w];
oldpossivel[last] = possivel;
if(w == z){
if(px == py) possivel = 0;
return;
}
pai[z] = w;
peso[w] += peso[z];
if(px == py) ligapai[z] = 1;
else ligapai[z] = 0;
}
void undo(){
int w = oldw[last] , z = oldz[last];
peso[w] = oldpeso[last];
pai[z] = oldpai[last];
ligapai[z] = oldliga[last];
possivel = oldpossivel[last];
last--;
}
void divide_and_conquer(int ini,int fim){
if(!possivel) return;
if(ini == fim){
if(possivel){
if(find(e1[ini]) != find(e2[ini])) ans++;
else if(parity(e1[ini]) == parity(e2[ini])) ans++;
}
return;
}
int meio = (ini+fim)/2;
for(int i = meio + 1;i<=fim;i++){
join(e1[i],e2[i]);
}
divide_and_conquer(ini,meio);
for(int i = meio + 1;i<=fim;i++){
undo();
}
for(int i = ini;i<=meio;i++){
join(e1[i],e2[i]);
}
divide_and_conquer(meio+1,fim);
for(int i = ini;i<=meio;i++){
undo();
}
}
int main(){
scanf("%d %d",&N,&M);
for(int i = 1;i<=N;i++){
pai[i] = i;
peso[i] = 1;
ligapai[i] = 0;
}
possivel = 1;
for(int i = 1;i<=M;i++){
scanf("%d %d",&e1[i],&e2[i]);
}
divide_and_conquer(1,M);
printf("%d\n",ans);
return 0;
}
