UVa 10935 Throwing cards away I Solution

#include<stdio.h>
#include<math.h>
int main()
{
int c,p,deck[55],n,i,j,k,x,r;
while(scanf("%d",&n)==1)
{
if(n==0)break;
if(n==1)printf("Discarded cards:\nRemaining card: 1\n");
else
{
printf("Discarded cards: 1");
for(i=1;i<=n;i++)deck[i]=1;
deck[1]=0;
x=1;
c=0;
for(i=1;i<=n;i++)
{
for(j=1;j<=n;j++)
{
if(deck[j]==1)c++;
if(x==n-1)break;
if(c==2)
{
deck[j]=0;
printf(", %d",j);
c=0;
x++;
}
}
}
for(i=1;;i++)
{
if(pow(2,i)>=n)
{
p=(long)pow(2,i);
break;
}
}
r=p-((p-n)*2);
printf("\nRemaining card: %d\n",r);
}
}
return 0;
}