C++ :

#include <cstdlib>
#include <cstdio>
#include <iostream>
using namespace std;
int n,k,m,cs=0,dian[300],ran=500,a,b;bool xian[300][300]={0};
int scan(int s)
{
    for(int i=1;i<=m;i++)
    {
        bool ok=1;
        for(int j=1;j<=s-1;j++)
        {
			if(xian[j][s]==1&&dian[j]==i)
			{
				ok=0;break;
			}
        }
        if(!ok) continue;
        dian[s]=i;
        if(s==n)
            cs++;
        else
            scan(s+1);
        dian[s]=ran;
    	ran++;
    }
}
int main()
{
    scanf("%d%d%d",&n,&k,&m);
    for(int i=1;i<=k;i++)
    {
        scanf("%d%d",&a,&b);
        xian[a][b]=1;
        xian[b][a]=1;
    }
    scan(1);
    printf("%d",cs);
    return 0;
}

Pascal :

var s,r,x,y,i,n,k,m:longint;l,f:array[0..101] of longint;a:array[0..10001,1..2] of longint;
procedure p1(x,y:longint);
begin
  r:=r+1;
  a[r,1]:=y;a[r,2]:=f[x];
  f[x]:=r;
end;
procedure try(x:longint);
var i:longint;c:array[1..6] of longint;
begin
  if x>n then s:=s+1
    else
      begin
        for i:=1 to k do c[i]:=0;
        i:=f[x];
        while i>0 do
          begin
            c[l[a[i,1]]]:=1;
            i:=a[i,2];
          end;
        for i:=1 to k do
          if c[i]=0 then
            begin
              l[x]:=i;
              try(x+1);
            end;
      end;
end;
begin
  readln(n,m,k);
  for i:=1 to m do
    begin
      read(x,y);
      if x<y then p1(y,x)
        else p1(x,y);
    end;
  try(1);
  writeln(s);
end.