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#include <stdio.h>
int euler_phi(int n)
{
int phi = n;
if (n % 2 == 0) {
while (n % 2 == 0)
n /= 2;
phi /= 2;
}
for (int i = 3; i*i <= n; i++) {
if (n % i == 0) {
while (n % i == 0)
n /= i;
phi /= i;
phi *= (i-1);
}
}
if (n > 1)
phi = phi / n * (n-1);
return phi;
}
int main()
{
long long cnt = 0;
for (int i = 2; i <= 1000000; i++)
cnt += euler_phi(i);
printf("%lld\n", cnt);
}
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