ll d[390625];
ll es[2d5];
ll@n,@k;
rep(i,n){
	ll e=0;
	string@s;
	rep(j,k){
		e=e*5+(s[j]-'0');
	}
	es[i]=e;
	d[e]+=1;
}
ll m=1;
rep(o,8){
	rrep(i,5**(7-o)){
		rrep(j,m*4){
			d[i*m*5+j]+=d[i*m*5+j+m];
		}
	}
	m*=5;
}
ll z=0;
rep(i,n){
	ll e=es[i];
	if(d[e]>1){
		z+=1;
	}
}
wt(z);