描述:
Huanhuan challenges you to a simple math problem.
Define F(x) as the sum of the decimal digits of xx.
For example: F(123)=1+2+3=6, F(700)=7+0+0=7.
Huanhuan wants you to calculate the sum of F(j) for every i,j that satisfy 1≤j≤i≤n andi,j are coprime.
More formally, calculate
输入:
There are only one test case with a single integer n(1≤n≤105)n(1≤n≤105).
输出:
Print one integer, the answer of
样例输入:
3
样例输出:
5
翻译:
标题:一个简单的数学问题
描述:
欢欢给你一个简单的数学问题挑战你。
定义F(x)作为十进制数的和。
例如:F(123)=1+2+3=6, F(700)=7+0+0=7.
欢欢希望计算F(j)满足每个i,j的总和,且1≤j≤i≤n,i和j是互质数。
更严格的说,是计算