题目描述
Consider a table G of size n×m such that G(i,j)=GCD(i,j) for all 1≤i≤n,1≤j≤m. GCD(a,b) is the greatest common divisor of numbers a and b.
You have a sequence of positive integer numbers a1,a2,...,ak. We say that this sequence occurs in table G if it coincides with consecutive elements in some row, starting from some position. More formally, such numbers 1≤i≤n and 1≤j≤m-k+1 should exist that G(i,j+l-1)=al for all 1≤l≤k.
Determine if the sequence a occurs in table G.
The first line contains three space-separated integers n, m and k (1≤n,m≤1012; 1≤k≤10000). The second line contains k space-separated integers a1,a2,...,ak (1≤ai≤1012).
Print a single word "YES", if the given sequence occurs in table G, otherwise print "NO".
100 100 5
5 2 1 2 1
YES
100 8 5
5 2 1 2 1
NO
100 100 7
1 2 3 4 5 6 7
NO
Sample 1. The tenth row of table G starts from sequence {1, 2, 1, 2, 5, 2, 1, 2, 1, 10}. As you can see, elements from fifth to ninth coincide with sequence a.
Sample 2. This time the width of table G equals 8. Sequence a doesn't occur there.