#include <cstdio>
#define buff_size 1<<19

char buff[buff_size];int pos;
int i,n,m,v[100001],x,y,aux,sz[100001],nr=0;
FILE*f=freopen("dfs.in","r",stdin);
FILE*g=freopen("dfs.out","w",stdout);

inline void read(int &nr)
{
    while(buff[pos] < '0' || buff[pos] > '9') if(++pos == buff_size) fread(buff,  1,buff_size, stdin), pos = 0;
    nr = 0;
    while('0' <= buff[pos] && buff[pos] <= '9')
    {
        nr = (nr<<1)+(nr<<3)+ buff[pos] - '0';
        if(++pos == buff_size) fread(buff, 1, buff_size, stdin), pos = 0;
    }
}
char outBuff[buff_size];
int outPtr;

inline void putChar(const char &C) {
    outBuff[outPtr++] = C;
    if (outPtr == buff_size) {
        fwrite(outBuff, 1, buff_size, stdout);
        outPtr = 0;
    }
}

inline  void write(int X) {
    static char digs[10];
    int n = 0, q;
    do {
        q = X / 10;
        digs[n++] = X - (q << 1) - (q << 3) + '0';

        X = q;
    } while (X);
    while (n--) {
        putChar(digs[n]);
    }
    putChar('\n');
}
int main()
{   fread(buff,  buff_size,1, stdin);
    read(n);read(m);
    for(i=1; i<=n; i++)   v[i]=i,sz[i]=1;
    for(i=1;i<=m;i++)
    {read(x);read(y);
     while(x!=v[x]) aux=v[v[x]],v[x]=aux,x=aux;
     while(y!=v[y]) aux=v[v[y]],v[y]=aux,y=aux;
     if(x!=y){
            nr++;
            if(sz[x]<sz[y]) v[x]=y,sz[y]+=sz[x];
            else v[y]=x,sz[x]+=sz[y];
        }
    }
   write(n-nr);
   fwrite(outBuff, 1, outPtr, stdout);
}