#include <stdio.h>
int m,n,a[4097][4097],nr=0;
int main()
{int i,j,k;
FILE *f;
f=fopen("triplete.in","r");
fscanf(f,"%d %d",&n,&m);
for (k=1;k<=m;k++)
    {fscanf(f,"%d %d",&i,&j);
    a[i][j]=1;
    }
fclose(f);
for (i=2;i<=n;i++)
    for (j=i+1;j<=n;j++)
        if (a[i][j]==1)
            if ((a[i-1][j-1]==1)&&(a[i-1][j]==1))
               nr++;        
FILE *g;
g=fopen("triplete.out","w");
fprintf(g,"%d",nr);
fclose(g);
return 0;
    }