#include<stdio.h>
#include<stdlib.h>
#define D 5000

struct cislo {
  int dig[D];
  int dn;
  };

struct cislo K[101][101];  
int buf[512][128];
int bufs;

void print(struct cislo *C) {
  int k;
  /* printf("%d ",C->dn); */
  printf("%d",C->dig[C->dn-1]);
  for (k=C->dn-2; k>=0; k--) printf("%03d",C->dig[k]);
  }

void mul(struct cislo *C1,struct cislo *C2,struct cislo *C3) {
  int i,j,over;
  C3->dn=C1->dn+C2->dn-1;
  for (i=0; i<C1->dn+C2->dn-1; i++) C3->dig[i]=0;
  /* printf("DEB: called %d %d\n",C1->dn,C2->dn); */
  for (i=0; i<C1->dn; i++) for (j=0; j<C2->dn; j++) C3->dig[i+j]+=C1->dig[i]*C2->dig[j];
  over=0;
  /* print(C3); */
  for (i=0; over||(i<C3->dn); i++) {
    if (i==C3->dn) C3->dig[C3->dn++]=0;
    C3->dig[i]+=over;
    over=C3->dig[i]/1000;
    C3->dig[i]%=1000;
    }
  }

void mulS(struct cislo *C, int k) {
  int i,over;
  over=0;
  for (i=0; i<C->dn; i++) {
    C->dig[i]*=k;
    C->dig[i]+=over;
    over=(C->dig[i])/1000;
    C->dig[i]%=1000;
    }
  if (over) C->dig[C->dn++]=over;
  }

void mulD(struct cislo *C, int k) {
  int i,over;
  if (k==1) return;
  over=0;
  for (i=C->dn-1; i>=0; i--) {
    C->dig[i]+=1000*over;
    over=C->dig[i]%k;
    C->dig[i]/=k;
    }
  for (i=C->dn-1; (i>0)&&(C->dig[i]==0); i--);
  C->dn=i+1;
  }

void init(void) {
  int i,j,k;
  for (i=0; i<=100; i++) for (j=0; j<=i; j++) {
    K[i][j].dig[0]=1;
    K[i][j].dn=1;
    for (k=0; k<j; k++) {
      mulS(&K[i][j],i-k);
      mulD(&K[i][j],k+1);
      }
    }
  }

void compute(struct cislo *C,int B,int L) {
  int b1,b2;
  int l1,l2;
  int i;
  struct cislo C1,C2,C0;
  b1=bufs++; l1=0;
  b2=bufs++; l2=0;
  for (i=1; i<L; i++) 
    if (buf[B][i]<buf[B][0])
      buf[b1][l1++]=buf[B][i];
    else  
      buf[b2][l2++]=buf[B][i];
  /*    
  for (i=0; i<K[l1+l2][l1]->dn; i++) C->dg[i]=K[l1+l2][l1]->dg[i];
  C->dn=K[l1+l2][l1]->dn;
  */
  if (l1==0) {
    C1.dn=1; C1.dig[0]=1;
    }
  else  
    compute(&C1,b1,l1);
  if (l2==0) {
    C2.dn=1; C2.dig[0]=1;
    }
  else  
    compute(&C2,b2,l2);
  mul(&K[l1+l2][l1],&C1,&C0);
  mul(&C0,&C2,C);
  /*
  printf("DEB: ");
  print(&K[l1+l2][l1]);  
  printf(" ");
  print(&C1);
  printf(" ");
  print(&C2);
  printf(" ");
  print(&C0);
  printf("\n");
  for (i=0; i<L; i++) printf("%d ",buf[B][i]);
  print(C);
  printf("\n");
  */
  }

int main(void) {
  int i,N;
  struct cislo C;
  init();
  /* print(&K[100][2]); printf("\n"); */
  scanf("%d",&N);
  while (N) {
    for (i=0; i<N; i++) scanf("%d",&buf[0][i]);
    bufs=1;
    compute(&C,0,N);
    print(&C);
    printf("\n");
    scanf("%d",&N);
    }
  return 0;
  }