11 lines
162 B
C++
11 lines
162 B
C++
#include<cstdio>
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using namespace std;
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int main()
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{
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double r1,r2;
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scanf("%lf%lf",&r1,&r2);
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double ans=1.0/(1.0/r1+1.0/r2);
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printf("%.2lf\n",ans);
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return 0;
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}
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