diff --git a/8.16/M-PairsFormingLCM/Readme.md b/8.16/M-PairsFormingLCM/Readme.md
index cc02b16..e973798 100644
--- a/8.16/M-PairsFormingLCM/Readme.md
+++ b/8.16/M-PairsFormingLCM/Readme.md
@@ -1,9 +1,11 @@
-# 题目
-* 链接
+# M - Pairs Forming LCM
+* https://vjudge.net/contest/509210#problem/M
 ### 题意
-
+给n,lcm(i, j) = n and (i ≤ j).
 ### 做法
-
+质因数分解n=p1^k1*p2^k2
+ans*=(2k[i]+1);(i=0~k,j=0~k,去掉重复的k,k)
+ans=ans/2+1;(i<=j,补上k,k)
 ### 关键词
 
 ### 易错点