#include
int binsearch(int a[],int ,int,int);
int main()
{
int n,i,x;
scanf("%d",&n);
scanf("%d",&x);
int a[n];
for(i=0;i
{
scanf("%d",&a[i]);
}
int lb=0,ub=n-1;
int pos=binsearch(a,lb,ub,x);
if(pos==-1)
printf("unsuccessful\n");
else
printf("%d\n",pos+1);
return 0;
}
int binsearch(int a[],int lb,int ub,int x)
{
int mid;
while(lb<=ub)
{
mid=(lb+ub)/2;
if(a[mid]==x)
return mid;
else if(a[mid]>x)
ub=mid-1;
else
lb=mid+1;
}
return -1;
}