tjut 3501

#include <iostream>#include <cmath>using namespace std;int jisuan(int x){    int i,res=x;    for(i=2;i<(int)sqrt(x*1.0)+1;i++)        if(x%i==0)        {            res=res/i*(i-1);            while(x%i==0)            x/=i;        }        if(x>1)        res=res/x*(x-1);        return res;}int main(void){    unsigned __int64 n;    while(scanf("%I64d", &n), n)    {        unsigned __int64 sum = n * (n + 1) / 2 - n, res;        res = sum - (n * jisuan(n) / 2);        printf("%I64d\n", res % 1000000007);    }    return 0;}