ll@n,@q,@a[n],c[],d[],@b[q];
rep(i,n){
	c[i]=i;
}
rep(j,q){
	ll w=ll_inf;
	rep(i,n){
		w<?=c[i];
		d[i]=w;
		w+=1;
	}
	w=d[n-1];
	rrep(i,n){
		c[i]=a[i]==b[j]?(w<?=d[i]):ll_inf;
		w+=1;
	}
}
wt(min(c(n)));