delete pics to save space

7.2480.cpp

@@ -0,0 +1,48 @@
+#include<cstdio>
+#include<cstring>
+#include<algorithm>
+using namespace std;
+typedef long long LL;
+const int maxn=65536;
+int p[maxn],v[maxn],ph[maxn],cnt;
+LL n,res;
+inline int phi(int x)
+{
+	LL res=x;
+	for(LL i=2;i*i<=x;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()
+{
+#ifdef local
+	freopen("pro.in","r",stdin);
+#endif
+	/*
+	ph[1]=1;
+	for(int i=2;i<maxn;i++)
+	{
+		if(!v[i]) { v[i]=i; ph[i]=i-1; p[cnt++]=i; }
+		for(int j=0;j<cnt&&(long long)p[j]*i<maxn&&p[j]<=v[i];j++)
+		{
+			v[p[j]*i]=p[j];
+			ph[p[j]*i]=ph[i]*(p[j]<v[i]?p[j]-1:p[j]);
+		}
+	}
+	*/
+	while(scanf("%d",&n)==1)
+	{
+		res=0;
+		for(LL i=1;i*i<=n;i++) if(n%i==0)
+		{
+			res+=i*phi(n/i);
+			if(i*i<n) res+=n/i*phi(i);
+		}
+		printf("%lld\n",res);
+	}
+	return 0;
+}