_==0 "exec" "gawk" "-f" "$0"
function f(a,n,x,y,	i) {
	for (i=2;i<=n;i++) if (a[i-1]*y>a[i]*x) return "NO"
	return "YES"
}
NR==1{x=$1;y=$2}
NR==2{n=$0}
NR==3{split($0,a," ")}
END{print f(a,n,x,y)}