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Cod sursa(job #981718)
#include<stdio.h>
int v[1000002];
long long min(long long a,long long b)
{
return a<b?a:b;
}
int main()
{
freopen("mins.in","r",stdin);
freopen("mins.out","w",stdout);
long long n,m,i,j,s=0,max,p;
scanf("%lld%lld",&n,&m);
max=min(n,m)-1;
for(i=2;i<=max;++i)
{
if(v[i]==0)
{
for(j=i;j<=max;j+=i)
++v[j];
p=i*i;
for(j=p;j<=max;j+=p)
v[j]=-2000000000;
}
else if(v[i]%2==0)
s+=((n-1)/i)*((m-1)/i);
else
s-=((n-1)/i)*((m-1)/i);
}
printf("%lld\n",s+(n-1)*(m-1));
return 0;
}