void ordon123(int n, int a[])
{
int nr1=0,nr2=0,nr3=0,k=0;
for (int i=0;i<n;++i)
{
if (a[i]==1) nr1++;
if (a[i]==2) nr2++;
if (a[i]==3) nr3++;
}
for (int i=1;i<=nr1;++i)
{
a[k]=1; k++;
}
for (int i=1;i<=nr2;++i)
{
a[k]=2; k++;
}
for (int i=1;i<=nr3;++i)
{
a[k]=3; k++;
}
}