20 lines
307 B
C++
20 lines
307 B
C++
#include<cstdio>
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typedef long long LL;
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int main()
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{
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LL n;
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scanf("%lld",&n);
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LL ans=n,i;
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for(i=2;i*i<=n;++i)
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if(n%i==0)
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{
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int b=0;
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while(n%i==0) ++b,n/=i;
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ans/=i;
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ans*=b*i-b+i;
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}
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if(n>1) ans/=n,ans*=n+n-1;
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printf("%lld\n",ans);
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return 0;
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}
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