public static boolean isDistanceOneSimple(String s1, String s2) {
		int m=s1.length(), n=s2.length();
		if (m==n) {
			int c=0;
			for (int i=0;i<m;++i) c+=s1.charAt(i)==s2.charAt(i)?0:1;
			return c==1;
		} else if (m+1==n) return insertOneCharacter(s1, s2);
		  else if (m==n+1) return insertOneCharacter(s2, s1);
		  else return false;
	}