ll n,a,b,z;{rd(n++,a);Matrixc(n,n);REP(a)rd(a,b),c[a][b]=c[b][a]=1;c=n*c-c*c;rep(i,n)rep(j,i)z+=(c[i][j]|c[i][1..j-1]|c[j][1..])>=0;wt(z);}