#include <bits/stdc++.h>

#define N 200006

#define setIO(s) freopen(s".in","r",stdin)

using namespace std;

int edges=1;

int hd[N],to[N<<1],nex[N<<1],dep[N],ev[N],od[N],fa[N<<1],vis[N<<1],gg[N],OD,EV;

void add(int u,int v)

{

    nex[++edges]=hd[u],hd[u]=edges,to[edges]=v;

}

void dfs(int u,int ff)

{

    gg[u]=1;

    for(int i=hd[u];i;i=nex[i])

    {

        int v=to[i];

        if(vis[i]) continue;

        vis[i]=vis[i^1]=1;

        if(!gg[v])

        {

            dep[v]=dep[u]+1;

            fa[v]=i;

            dfs(v,u);

            od[u]+=od[v];

            ev[u]+=ev[v];

        }

        else

        {

            if(dep[v]>dep[u]) continue;

            if((dep[u]-dep[v])%2==0)

            {

                // 奇环

                od[u]++;

                od[v]--;

                ++OD;

            }

            else

            {

                ev[u]++;

                ev[v]--;

                ++EV;

            }

        }

    }

}

int main()

{

    // setIO("input");

    int i,j,n,m;

    scanf("%d%d",&n,&m);

    for(i=1;i<=m;++i)

    {

        int x,y;

        scanf("%d%d",&x,&y);

        add(x,y),add(y,x);

    }

    for(i=1;i<=n;++i) if(!gg[i]) dfs(i,0);

    int ans=0;

    for(i=1;i<=n;++i) if(od[i]==OD&&ev[i]==0&&fa[i]) ++ans;

    if(OD==1) ++ans;

    printf("%d\n",ans);

    return 0;

}