10820 Send a Table（欧拉函数）(二)
i = 2; i <= m && i <= num; i ++) {
if (num % i == 0) {
ans = (ans - ans / i);
while (num % i == 0) {
num /= i;
}
}
}
if (num != 1) {
ans = (ans - ans / num);
}
return ans;
}
int main() {
for (i = 2; i <= 50001; i ++) {
sum[i] = save(i);
}
while (~scanf("%d", &n) && n) {
out = 1;
for (i = 2; i <= n; i ++) {
out += sum[i] * 2;
}
printf("%d\n", out);
}
return 0;
}