#include <stdio.h>
#include <stdlib.h>

int *a[5001];
int n,m,nr,x,y,i,j,k,viz[5001];

int main()
{
    freopen("triplete.in","r",stdin);
    freopen("triplete.out","w",stdout);
    
    scanf("%d %d", &n,&m);
    for (i=1;i<=n;++i)
    {
        a[i]=(int *) realloc(a[i], sizeof(int));
        a[i][0]=0;
    }
    
    for (i=1;i<=m;++i)
    {
         scanf("%d %d", &x,&y);
         a[x][0]++;
         a[x]=(int *) realloc(a[x],(a[x][0]+1)*sizeof(int)); 
         a[x][a[x][0]]=y;
         a[y][0]++;
         a[y]=(int *) realloc(a[y],(a[y][0]+1)*sizeof(int));
         a[y][a[y][0]]=x;
    }
    for (i=1;i<=n;++i)   
        if (a[i][0]==3) nr++;
    printf("%d", nr);
    return 0;
}